Ataman
02-28-2014, 06:57 PM
Mommy's little secret
As we gather to mark the festive season, here's one juicy morsel mom won't be dishing up: that guy you call your dad may not be. DNA testing has revolutionized medical science, CAROLYN ABRAHAM reports, but it also has uncovered the myth of female monogamy. Now doctors are wondering how to break the news to men
The Globe and Mail, By CAROLYN ABRAHAM, Saturday, December 14, 2002 – Print Edition, Page F1
They came to the hospital together, a husband, a wife and the little daughter they feared had been cursed by inheritance. Since birth, she had struggled to breathe, and all the signs pointed to cystic fibrosis.
If the girl truly had the incurable disease that clogs the lungs, she had to have received two copies of a CF gene, one from each parent. Tests at the Hospital for Sick Children in Toronto confirmed the family's worst fears -- and then some.
The girl was indeed afflicted. Her mom carried one of the culprit genes. But her dad, the doctors discovered, was quite a different story. His DNA showed no sign of a CF gene, which means he is not a carrier and he is not her dad.
Hospital staff have felt bound to keep the secret from him. But when they told the mom, it came as no surprise; it rarely does.
"It is probably true in a lot of families, that daddy is not who you think it is," says Steve Scherer, a senior scientist in department of genetics at the Hospital for Sick Children.
As families gather this festive season, here is a spicy fact that mothers might be loath to dish out at the holiday table: It's now widely accepted among those who work in genetics that roughly 10 per cent of us are not fathered by the man we believe to be dad.
Geneticists have stumbled upon this phenomenon in the course of conducting large population studies and hunting for genes that cause diseases such as cystic fibrosis. They find full siblings to be half-siblings, fathers who are genetic strangers to more than one of their children and uncles who are much closer to their nieces and nephews than anyone might guess. Lumped under the heading of "pedigree errors," these so-called mis-paternities, false paternities and non-paternities are all science jargon for the unwitting number of us who are chips off someone else's block.
The proverbial postman seems to be ringing twice in everyone's neighbourhood. Non-paternity is believed to cut across all socio-economic classes and many cultures. Factor it into genealogical attempts to trace ancestry and it can snap entire branches from a family tree. Considered in light of long-held views about sexual behaviour, it exposes the myth of female monogamy and utterly shakes the assumption that women are biologically driven to single-mate bliss.
The widespread use of DNA analysis has presented science and society with all sorts of new ethical problems, and now it's pulling this naked truth out of the closet and into the courtroom. Men who call themselves "Duped Dads" are looking for legal redress to protect themselves against paternity fraud, raising questions about the definition of fatherhood. Several U.S. states are considering legislation that could exempt non-biological fathers from having to pay child support.
Even the most learned among us are grappling with the implications. Last month, the 10-per-cent non-paternity rate was cited during a science seminar for judges in Halifax.
"The judges were just shocked; they really couldn't get over how many people this would affect," Dr. Scherer said. "They kept saying things about all those poor people who might be misled -- never realizing that one of them might actually be among them!"
The notion of a woman carrying the child of someone other than her partner is older than the Christmas story itself. No geneticist believes non-paternity to be purely the product of modern immorality; they have been tripping over the infidelities of earlier generations for decades.
Cheryl Shuman, director of genetic counselling at the Hospital for Sick Children, said that 15 years ago, when genetic tests were less powerful, researchers had to draw blood from a child, his or her parents and both sets of grandparents. "Sometimes we'd get a call from the grandmother, and she'd say, 'Listen, my son, or my daughter, doesn't know that their father is not their real father. . . .' "
In the interests of maintaining family peace, Ms. Shuman said, the tests would be dismissed as "uninformative."
Over the years, the hospital has relied on the advice of lawyers and ethicists to develop policies for handling the situation. For example, its consent form now warns what a genetic test can reveal. Parents "will sometimes giggle in the waiting room when they read the paragraph about non-paternity," Ms. Shuman said. "But then we get the phone call later, forewarning us as to what we might find."
When a test disqualifies a father, "most women do express some surprise, but then there is a resignation, or an acceptance that they were kind of half anticipating this was going to happen. But then all this is followed very quickly by panic and questions as to whether or not we will betray their confidentiality."
If the case involves an expectant mother, Ms. Shuman explained, the hospital's legal obligation is clear: The developing baby is considered part of the mother and the results of the tests therefore belong to her.
After birth, the course of action is less clear, she said, but lawyers advise that the child is to be considered the patient, whose needs trump those of the parents. Since telling the father could trigger a breakup and leave the child without proper support, the hospital keeps the secret. Sometimes it can be a whopper.
In one family with four daughters, the DNA analysis was so surprising that counsellors asked the mother to explain. "It turned out that the daughters had three different fathers," said Peter Ray, a scientist at the hospital. "We cannot make any conclusions based on the family structures as they are presented to us."
In the research world, when scientists come across a father in a mismatched family, they toss the sample. If pedigree errors are not caught, Dr. Scherer said, they can wreak statistical havoc with a study: "People have made careers designing software to catch these kinds of things."
Sample mix-ups can skew results, as can an extremely rare condition discovered in 1989 in which a child inherits two copies of the same chromosome from one parent, obscuring the contribution of the other. But as the number of gene hunts and diagnostic tests has grown and grown, the leading cause of these anomalies has proved to be mistaken fatherhood.
Some peg the range at 5 to 10 per cent; others, such as Jeanette Papp of the University of California at Los Angeles, feel that 15 per cent is reasonable for the Western world, even if there is no hard evidence. "It's hard to do studies on these things for ethical reasons," says Dr. Papp, director of genotyping and sequencing in UCLA's department of human genetics. "I mean, how do you tell people what you're really looking for?"
A British survey conducted between 1988 and 1996 by Robin Baker, a former professor at the University of Manchester, confirmed the 10-per-cent figure. That seems high to skeptics such as Dalhousie University geneticist Paul Neumann, although even he admitted that "my colleague, who's a woman, tells me women have no trouble believing it. . . . It's the men who can't."
Bernard Dickens, a specialist in health law and policy at the University of Toronto, said that in another British example, the non-paternity rate was three times that.
In the early 1970s, a schoolteacher in southern England assigned a class science project in which his students were to find out the blood types of their parents. The students were then to use this information to deduce their own blood types (because a gene from each parent determines your blood type, in most instances only a certain number of combinations are possible). Instead, 30 per cent of the students discovered their dads were not their biologically fathers.
"The classroom was, of course, not the ideal place to find out this information," said Prof. Dickens, who is often consulted on ethical issues by geneticists at the Hospital for Sick Children.
He feels, as do many researchers, that culture can determine whether false paternity is very high or very low. For example, in Muslim Egypt, the integrity of lineage is so important that neither sperm or egg donation nor adoption is permitted, let alone sexual indiscretion.
But false paternity causes obvious problems for anyone who values a clear pedigree and makes it a statistical impossibility to trace the true identity of our ancestors back more than a few generations.
Robert Moyzis, a molecular geneticist at the University of California at Irvine, recently had to break this news to a friend who had spent considerable energy and resources compiling a family history that stretched back 1,000 years. "I had to plug the numbers into a computer model and prove it to him. The chances that he was related to the ancestor he thought were zero."
Logistically, it may seem that only men are naturally programmed for multiple partners. After all, they can produce sperm by the thousands 24 hours a day, seven days a week, and do it well into their retirement years.
Women, on the other hand, are limited to the eggs they were born with, maturing one a month and not much past their fourth decade of life. The precious few shots that women have at reproduction may drive them to seek the best mate for prospective offspring -- though the decision might be wholly unconscious.
This notion is bolstered by the "sperm wars" theory, in which Britain's Dr. Baker has noted that sperm of two different men can effectively battle over the spoils of fertilizing the egg in a woman's reproductive tract.
In 1999, a questionnaire in Britain found that most women tended to be unfaithful to their long-term partners around the time they were most fertile.
That same year, researchers at St. Andrew's University in Scotland concluded that women seem to desire different types of men at different times of the month. When they are most likely to conceive, they are attracted to men who have very masculine features, preferring more feminine men when they are not ovulating.
The researchers suggested that women may subconsciously feel that beefy men may make a better biological contribution to a baby, but softer features may signal a better father.
And strangers may have a biological advantage. "There is actually data from Britain," said sexual-behaviour expert Judith Lipton, "that suggests a woman may be more likely to conceive with a fresh partner because a woman can essentially develop antibodies against her regular partner's sperm, so that she may be more likely to be impregnated by fresh sperm."
Between 30 and 50 per cent of women cheat on their partners, compared with 50 to 80 per cent of men, said Dr. Lipton, a psychiatrist with the Swedish Medical Center in Washington who last year co-wrote The Myth of Monogamy with her husband, David Barash.
"This jibes with the idea that as many as 10 per cent of these relations may result in pregnancy," she said, explaining that women may cheat as an escape from a bad marriage, for revenge on a cheating partner, to find a better provider, or just for fun.
All this messing around might have been predicted by animal behaviour, but it has been only recently that researchers learned just how hard faithful females are to find in any species.
Dr. Barash, a zoologist and professor of psychology at the University of Washington, explained that while it was generally known that most mammals are rarely monogamous, certain species were held up as paragons of virtue. Scientists believed, for example, fidelity was definitely for the birds. "But not even the swans are monogamous, and they were the poster children for monogamy. Despite their waterfront property, they still sneak around with the neighbours."
With the 1980s advent of DNA fingerprinting, a quick molecular test that, among other things, tells scientists whether two creatures are genetically related, researchers have realized social monogamy has little bearing on sexual monogamy in the animal kingdom.
"A lot of hanky-panky goes on even if two creatures set up house together," Dr. Barash said.
Despite thousands of hours of observation, birds managed to fool not only their mates into thinking they were faithful, but their observers. Yet DNA tests show that 10 to 50 per cent of birds are fathered by a male other than the one sharing the nest.
"We always knew the possibility was there for males to be available and receptive to EPC -- extra-pair copulation -- but what was not known was that the mated females would do the same thing," Dr. Barash said.
In part, researchers figured females would be deterred from cheating since they had more to lose than a male by fooling around -- their mate might stop foraging to feed the hungry offspring, cutting off the animal equivalent of child support, or worse, turn violent. Yet this, he said, seems only to have inspired females to perfect the art of secrecy and deception: They persistently sneak off in search of stronger genes, better feeding grounds, good providers and protectors.
These trysts may have been overlooked, said Frances Burton, an anthropologist at the University of Toronto, because the researchers were often male. "There is a weird double feedback thing that goes on when it comes to observing animals, particularly non-human primates. We impose upon the observations human prejudices . . . it can obfuscate whatever truth there is."
Even the fact that female animals actually derive enjoyment from copulation wasn't fully accepted until 1971, when Prof. Burton showed that female monkeys stimulated with an electric toothbrush did in fact reach orgasm. "Though they rarely did with male monkeys," she added, "because the males did not engage them for long enough periods."
Now the hope that fidelity is compatible with wildlife has all but vanished. DNA testing is crossing one species after another off the list. Of 4,000 mammalian species, only 3 per cent are still considered candidates. Birds, bees, snails, snakes, fish, frogs . . . not even mites are monogamous. You have slide well down the food chain before Dr. Barash will put his money on a contender: Diplozoon paradoxum,a parasitic flatworm found in the gills of freshwater fish. The first time two worms mate, their bodies are fused together for life.
None of this should imply that humans are incapable of monogamy, he added. "Saying something is natural is often used to justify unacceptable behaviour. It's natural to poop on the floor, but we spend a lot of time becoming house broken."
His wife, however, said the moral transgression of infidelity cannot compare with the deception of lying about paternity. She thinks paternity fraud should be considered a crime of the highest order.
"Reproductive deception is morally similar to rape," Dr. Lipton said. "If you trick someone into raising a baby not his own, and he puts 20 years of his life into an endeavour based on a falsehood, that is appalling.
"If I were the queen of the world, birth control, of any form, would be available to any woman who wants it and DNA testing would be available for all the men so that they would know who their babies are."
There are certainly those -- the "Duped Dads" among them -- who would agree with her.
Morgan Wise remembers how in 1999 the doctor rose from his chair, walked around the desk and sat down in front of him. Mr. Wise's youngest son had been diagnosed with cystic fibrosis years earlier, but a medical test showed Mr. Wise did not carry a CF gene.
"My first thought was that they must have misdiagnosed my son," the 40-year-old railway engineer from Big Spring, Tex., said in an interview this week.
But then the doctor looked him squarely in the eye and said: "Morgan, do you have any reason to think this boy might not be yours?"
The possibility seemed outlandish. He had been married to the same woman for 13 years and they had had three boys and a girl before they broke up in 1996. But for peace of mind, he decided to go ahead with paternity tests.
In March, 1999, the results arrived by mail -- a creased piece of paper telling him that not one of the three boys was his.
"I felt anger toward [my first wife] and sadness, and I felt so sorry for my kids," Mr. Wise recalled. "I told my boys, 'I love you all, you'll always be my sons, the only difference is now I'm not your birth father.' "
Despite this revelation, a district court judge ruled that Mr. Wise had to continue paying child support for the three boys. Based on a 500-year-old common law, most states operate on the presumption that a husband is the father of any child born to his wife during a marriage.
Mr. Wise took his case to the media, hophttp://www.canadiancrc.com/Newspaper...t_14DEC02.aspx
They came to the hospital together, a husband, a wife and the little daughter they feared had been cursed by inheritance. Since birth, she had struggled to breathe, and all the signs pointed to cystic fibrosis.
If the girl truly had the incurable disease that clogs the lungs, she had to have received two copies of a CF gene, one from each parent. Tests at the Hospital for Sick Children in Toronto confirmed the family's worst fears -- and then some.
The girl was indeed afflicted. Her mom carried one of the culprit genes. But her dad, the doctors discovered, was quite a different story. His DNA showed no sign of a CF gene, which means he is not a carrier and he is not her dad.
Hospital staff have felt bound to keep the secret from him. But when they told the mom, it came as no surprise; it rarely does.
"It is probably true in a lot of families, that daddy is not who you think it is," says Steve Scherer, a senior scientist in department of genetics at the Hospital for Sick Children.
As families gather this festive season, here is a spicy fact that mothers might be loath to dish out at the holiday table: It's now widely accepted among those who work in genetics that roughly 10 per cent of us are not fathered by the man we believe to be dad.
Geneticists have stumbled upon this phenomenon in the course of conducting large population studies and hunting for genes that cause diseases such as cystic fibrosis. They find full siblings to be half-siblings, fathers who are genetic strangers to more than one of their children and uncles who are much closer to their nieces and nephews than anyone might guess. Lumped under the heading of "pedigree errors," these so-called mis-paternities, false paternities and non-paternities are all science jargon for the unwitting number of us who are chips off someone else's block.
The proverbial postman seems to be ringing twice in everyone's neighbourhood. Non-paternity is believed to cut across all socio-economic classes and many cultures. Factor it into genealogical attempts to trace ancestry and it can snap entire branches from a family tree. Considered in light of long-held views about sexual behaviour, it exposes the myth of female monogamy and utterly shakes the assumption that women are biologically driven to single-mate bliss.
The widespread use of DNA analysis has presented science and society with all sorts of new ethical problems, and now it's pulling this naked truth out of the closet and into the courtroom. Men who call themselves "Duped Dads" are looking for legal redress to protect themselves against paternity fraud, raising questions about the definition of fatherhood. Several U.S. states are considering legislation that could exempt non-biological fathers from having to pay child support.
Even the most learned among us are grappling with the implications. Last month, the 10-per-cent non-paternity rate was cited during a science seminar for judges in Halifax.
"The judges were just shocked; they really couldn't get over how many people this would affect," Dr. Scherer said. "They kept saying things about all those poor people who might be misled -- never realizing that one of them might actually be among them!"
The notion of a woman carrying the child of someone other than her partner is older than the Christmas story itself. No geneticist believes non-paternity to be purely the product of modern immorality; they have been tripping over the infidelities of earlier generations for decades.
Cheryl Shuman, director of genetic counselling at the Hospital for Sick Children, said that 15 years ago, when genetic tests were less powerful, researchers had to draw blood from a child, his or her parents and both sets of grandparents. "Sometimes we'd get a call from the grandmother, and she'd say, 'Listen, my son, or my daughter, doesn't know that their father is not their real father. . . .' "
In the interests of maintaining family peace, Ms. Shuman said, the tests would be dismissed as "uninformative."
Over the years, the hospital has relied on the advice of lawyers and ethicists to develop policies for handling the situation. For example, its consent form now warns what a genetic test can reveal. Parents "will sometimes giggle in the waiting room when they read the paragraph about non-paternity," Ms. Shuman said. "But then we get the phone call later, forewarning us as to what we might find."
When a test disqualifies a father, "most women do express some surprise, but then there is a resignation, or an acceptance that they were kind of half anticipating this was going to happen. But then all this is followed very quickly by panic and questions as to whether or not we will betray their confidentiality."
If the case involves an expectant mother, Ms. Shuman explained, the hospital's legal obligation is clear: The developing baby is considered part of the mother and the results of the tests therefore belong to her.
After birth, the course of action is less clear, she said, but lawyers advise that the child is to be considered the patient, whose needs trump those of the parents. Since telling the father could trigger a breakup and leave the child without proper support, the hospital keeps the secret. Sometimes it can be a whopper.
In one family with four daughters, the DNA analysis was so surprising that counsellors asked the mother to explain. "It turned out that the daughters had three different fathers," said Peter Ray, a scientist at the hospital. "We cannot make any conclusions based on the family structures as they are presented to us."
In the research world, when scientists come across a father in a mismatched family, they toss the sample. If pedigree errors are not caught, Dr. Scherer said, they can wreak statistical havoc with a study: "People have made careers designing software to catch these kinds of things."
Sample mix-ups can skew results, as can an extremely rare condition discovered in 1989 in which a child inherits two copies of the same chromosome from one parent, obscuring the contribution of the other. But as the number of gene hunts and diagnostic tests has grown and grown, the leading cause of these anomalies has proved to be mistaken fatherhood.
Some peg the range at 5 to 10 per cent; others, such as Jeanette Papp of the University of California at Los Angeles, feel that 15 per cent is reasonable for the Western world, even if there is no hard evidence. "It's hard to do studies on these things for ethical reasons," says Dr. Papp, director of genotyping and sequencing in UCLA's department of human genetics. "I mean, how do you tell people what you're really looking for?"
As we gather to mark the festive season, here's one juicy morsel mom won't be dishing up: that guy you call your dad may not be. DNA testing has revolutionized medical science, CAROLYN ABRAHAM reports, but it also has uncovered the myth of female monogamy. Now doctors are wondering how to break the news to men
The Globe and Mail, By CAROLYN ABRAHAM, Saturday, December 14, 2002 – Print Edition, Page F1
They came to the hospital together, a husband, a wife and the little daughter they feared had been cursed by inheritance. Since birth, she had struggled to breathe, and all the signs pointed to cystic fibrosis.
If the girl truly had the incurable disease that clogs the lungs, she had to have received two copies of a CF gene, one from each parent. Tests at the Hospital for Sick Children in Toronto confirmed the family's worst fears -- and then some.
The girl was indeed afflicted. Her mom carried one of the culprit genes. But her dad, the doctors discovered, was quite a different story. His DNA showed no sign of a CF gene, which means he is not a carrier and he is not her dad.
Hospital staff have felt bound to keep the secret from him. But when they told the mom, it came as no surprise; it rarely does.
"It is probably true in a lot of families, that daddy is not who you think it is," says Steve Scherer, a senior scientist in department of genetics at the Hospital for Sick Children.
As families gather this festive season, here is a spicy fact that mothers might be loath to dish out at the holiday table: It's now widely accepted among those who work in genetics that roughly 10 per cent of us are not fathered by the man we believe to be dad.
Geneticists have stumbled upon this phenomenon in the course of conducting large population studies and hunting for genes that cause diseases such as cystic fibrosis. They find full siblings to be half-siblings, fathers who are genetic strangers to more than one of their children and uncles who are much closer to their nieces and nephews than anyone might guess. Lumped under the heading of "pedigree errors," these so-called mis-paternities, false paternities and non-paternities are all science jargon for the unwitting number of us who are chips off someone else's block.
The proverbial postman seems to be ringing twice in everyone's neighbourhood. Non-paternity is believed to cut across all socio-economic classes and many cultures. Factor it into genealogical attempts to trace ancestry and it can snap entire branches from a family tree. Considered in light of long-held views about sexual behaviour, it exposes the myth of female monogamy and utterly shakes the assumption that women are biologically driven to single-mate bliss.
The widespread use of DNA analysis has presented science and society with all sorts of new ethical problems, and now it's pulling this naked truth out of the closet and into the courtroom. Men who call themselves "Duped Dads" are looking for legal redress to protect themselves against paternity fraud, raising questions about the definition of fatherhood. Several U.S. states are considering legislation that could exempt non-biological fathers from having to pay child support.
Even the most learned among us are grappling with the implications. Last month, the 10-per-cent non-paternity rate was cited during a science seminar for judges in Halifax.
"The judges were just shocked; they really couldn't get over how many people this would affect," Dr. Scherer said. "They kept saying things about all those poor people who might be misled -- never realizing that one of them might actually be among them!"
The notion of a woman carrying the child of someone other than her partner is older than the Christmas story itself. No geneticist believes non-paternity to be purely the product of modern immorality; they have been tripping over the infidelities of earlier generations for decades.
Cheryl Shuman, director of genetic counselling at the Hospital for Sick Children, said that 15 years ago, when genetic tests were less powerful, researchers had to draw blood from a child, his or her parents and both sets of grandparents. "Sometimes we'd get a call from the grandmother, and she'd say, 'Listen, my son, or my daughter, doesn't know that their father is not their real father. . . .' "
In the interests of maintaining family peace, Ms. Shuman said, the tests would be dismissed as "uninformative."
Over the years, the hospital has relied on the advice of lawyers and ethicists to develop policies for handling the situation. For example, its consent form now warns what a genetic test can reveal. Parents "will sometimes giggle in the waiting room when they read the paragraph about non-paternity," Ms. Shuman said. "But then we get the phone call later, forewarning us as to what we might find."
When a test disqualifies a father, "most women do express some surprise, but then there is a resignation, or an acceptance that they were kind of half anticipating this was going to happen. But then all this is followed very quickly by panic and questions as to whether or not we will betray their confidentiality."
If the case involves an expectant mother, Ms. Shuman explained, the hospital's legal obligation is clear: The developing baby is considered part of the mother and the results of the tests therefore belong to her.
After birth, the course of action is less clear, she said, but lawyers advise that the child is to be considered the patient, whose needs trump those of the parents. Since telling the father could trigger a breakup and leave the child without proper support, the hospital keeps the secret. Sometimes it can be a whopper.
In one family with four daughters, the DNA analysis was so surprising that counsellors asked the mother to explain. "It turned out that the daughters had three different fathers," said Peter Ray, a scientist at the hospital. "We cannot make any conclusions based on the family structures as they are presented to us."
In the research world, when scientists come across a father in a mismatched family, they toss the sample. If pedigree errors are not caught, Dr. Scherer said, they can wreak statistical havoc with a study: "People have made careers designing software to catch these kinds of things."
Sample mix-ups can skew results, as can an extremely rare condition discovered in 1989 in which a child inherits two copies of the same chromosome from one parent, obscuring the contribution of the other. But as the number of gene hunts and diagnostic tests has grown and grown, the leading cause of these anomalies has proved to be mistaken fatherhood.
Some peg the range at 5 to 10 per cent; others, such as Jeanette Papp of the University of California at Los Angeles, feel that 15 per cent is reasonable for the Western world, even if there is no hard evidence. "It's hard to do studies on these things for ethical reasons," says Dr. Papp, director of genotyping and sequencing in UCLA's department of human genetics. "I mean, how do you tell people what you're really looking for?"
A British survey conducted between 1988 and 1996 by Robin Baker, a former professor at the University of Manchester, confirmed the 10-per-cent figure. That seems high to skeptics such as Dalhousie University geneticist Paul Neumann, although even he admitted that "my colleague, who's a woman, tells me women have no trouble believing it. . . . It's the men who can't."
Bernard Dickens, a specialist in health law and policy at the University of Toronto, said that in another British example, the non-paternity rate was three times that.
In the early 1970s, a schoolteacher in southern England assigned a class science project in which his students were to find out the blood types of their parents. The students were then to use this information to deduce their own blood types (because a gene from each parent determines your blood type, in most instances only a certain number of combinations are possible). Instead, 30 per cent of the students discovered their dads were not their biologically fathers.
"The classroom was, of course, not the ideal place to find out this information," said Prof. Dickens, who is often consulted on ethical issues by geneticists at the Hospital for Sick Children.
He feels, as do many researchers, that culture can determine whether false paternity is very high or very low. For example, in Muslim Egypt, the integrity of lineage is so important that neither sperm or egg donation nor adoption is permitted, let alone sexual indiscretion.
But false paternity causes obvious problems for anyone who values a clear pedigree and makes it a statistical impossibility to trace the true identity of our ancestors back more than a few generations.
Robert Moyzis, a molecular geneticist at the University of California at Irvine, recently had to break this news to a friend who had spent considerable energy and resources compiling a family history that stretched back 1,000 years. "I had to plug the numbers into a computer model and prove it to him. The chances that he was related to the ancestor he thought were zero."
Logistically, it may seem that only men are naturally programmed for multiple partners. After all, they can produce sperm by the thousands 24 hours a day, seven days a week, and do it well into their retirement years.
Women, on the other hand, are limited to the eggs they were born with, maturing one a month and not much past their fourth decade of life. The precious few shots that women have at reproduction may drive them to seek the best mate for prospective offspring -- though the decision might be wholly unconscious.
This notion is bolstered by the "sperm wars" theory, in which Britain's Dr. Baker has noted that sperm of two different men can effectively battle over the spoils of fertilizing the egg in a woman's reproductive tract.
In 1999, a questionnaire in Britain found that most women tended to be unfaithful to their long-term partners around the time they were most fertile.
That same year, researchers at St. Andrew's University in Scotland concluded that women seem to desire different types of men at different times of the month. When they are most likely to conceive, they are attracted to men who have very masculine features, preferring more feminine men when they are not ovulating.
The researchers suggested that women may subconsciously feel that beefy men may make a better biological contribution to a baby, but softer features may signal a better father.
And strangers may have a biological advantage. "There is actually data from Britain," said sexual-behaviour expert Judith Lipton, "that suggests a woman may be more likely to conceive with a fresh partner because a woman can essentially develop antibodies against her regular partner's sperm, so that she may be more likely to be impregnated by fresh sperm."
Between 30 and 50 per cent of women cheat on their partners, compared with 50 to 80 per cent of men, said Dr. Lipton, a psychiatrist with the Swedish Medical Center in Washington who last year co-wrote The Myth of Monogamy with her husband, David Barash.
"This jibes with the idea that as many as 10 per cent of these relations may result in pregnancy," she said, explaining that women may cheat as an escape from a bad marriage, for revenge on a cheating partner, to find a better provider, or just for fun.
All this messing around might have been predicted by animal behaviour, but it has been only recently that researchers learned just how hard faithful females are to find in any species.
Dr. Barash, a zoologist and professor of psychology at the University of Washington, explained that while it was generally known that most mammals are rarely monogamous, certain species were held up as paragons of virtue. Scientists believed, for example, fidelity was definitely for the birds. "But not even the swans are monogamous, and they were the poster children for monogamy. Despite their waterfront property, they still sneak around with the neighbours."
With the 1980s advent of DNA fingerprinting, a quick molecular test that, among other things, tells scientists whether two creatures are genetically related, researchers have realized social monogamy has little bearing on sexual monogamy in the animal kingdom.
"A lot of hanky-panky goes on even if two creatures set up house together," Dr. Barash said.
Despite thousands of hours of observation, birds managed to fool not only their mates into thinking they were faithful, but their observers. Yet DNA tests show that 10 to 50 per cent of birds are fathered by a male other than the one sharing the nest.
"We always knew the possibility was there for males to be available and receptive to EPC -- extra-pair copulation -- but what was not known was that the mated females would do the same thing," Dr. Barash said.
In part, researchers figured females would be deterred from cheating since they had more to lose than a male by fooling around -- their mate might stop foraging to feed the hungry offspring, cutting off the animal equivalent of child support, or worse, turn violent. Yet this, he said, seems only to have inspired females to perfect the art of secrecy and deception: They persistently sneak off in search of stronger genes, better feeding grounds, good providers and protectors.
These trysts may have been overlooked, said Frances Burton, an anthropologist at the University of Toronto, because the researchers were often male. "There is a weird double feedback thing that goes on when it comes to observing animals, particularly non-human primates. We impose upon the observations human prejudices . . . it can obfuscate whatever truth there is."
Even the fact that female animals actually derive enjoyment from copulation wasn't fully accepted until 1971, when Prof. Burton showed that female monkeys stimulated with an electric toothbrush did in fact reach orgasm. "Though they rarely did with male monkeys," she added, "because the males did not engage them for long enough periods."
Now the hope that fidelity is compatible with wildlife has all but vanished. DNA testing is crossing one species after another off the list. Of 4,000 mammalian species, only 3 per cent are still considered candidates. Birds, bees, snails, snakes, fish, frogs . . . not even mites are monogamous. You have slide well down the food chain before Dr. Barash will put his money on a contender: Diplozoon paradoxum,a parasitic flatworm found in the gills of freshwater fish. The first time two worms mate, their bodies are fused together for life.
None of this should imply that humans are incapable of monogamy, he added. "Saying something is natural is often used to justify unacceptable behaviour. It's natural to poop on the floor, but we spend a lot of time becoming house broken."
His wife, however, said the moral transgression of infidelity cannot compare with the deception of lying about paternity. She thinks paternity fraud should be considered a crime of the highest order.
"Reproductive deception is morally similar to rape," Dr. Lipton said. "If you trick someone into raising a baby not his own, and he puts 20 years of his life into an endeavour based on a falsehood, that is appalling.
"If I were the queen of the world, birth control, of any form, would be available to any woman who wants it and DNA testing would be available for all the men so that they would know who their babies are."
There are certainly those -- the "Duped Dads" among them -- who would agree with her.
Morgan Wise remembers how in 1999 the doctor rose from his chair, walked around the desk and sat down in front of him. Mr. Wise's youngest son had been diagnosed with cystic fibrosis years earlier, but a medical test showed Mr. Wise did not carry a CF gene.
"My first thought was that they must have misdiagnosed my son," the 40-year-old railway engineer from Big Spring, Tex., said in an interview this week.
But then the doctor looked him squarely in the eye and said: "Morgan, do you have any reason to think this boy might not be yours?"
The possibility seemed outlandish. He had been married to the same woman for 13 years and they had had three boys and a girl before they broke up in 1996. But for peace of mind, he decided to go ahead with paternity tests.
In March, 1999, the results arrived by mail -- a creased piece of paper telling him that not one of the three boys was his.
"I felt anger toward [my first wife] and sadness, and I felt so sorry for my kids," Mr. Wise recalled. "I told my boys, 'I love you all, you'll always be my sons, the only difference is now I'm not your birth father.' "
Despite this revelation, a district court judge ruled that Mr. Wise had to continue paying child support for the three boys. Based on a 500-year-old common law, most states operate on the presumption that a husband is the father of any child born to his wife during a marriage.
Mr. Wise took his case to the media, hophttp://www.canadiancrc.com/Newspaper...t_14DEC02.aspx
They came to the hospital together, a husband, a wife and the little daughter they feared had been cursed by inheritance. Since birth, she had struggled to breathe, and all the signs pointed to cystic fibrosis.
If the girl truly had the incurable disease that clogs the lungs, she had to have received two copies of a CF gene, one from each parent. Tests at the Hospital for Sick Children in Toronto confirmed the family's worst fears -- and then some.
The girl was indeed afflicted. Her mom carried one of the culprit genes. But her dad, the doctors discovered, was quite a different story. His DNA showed no sign of a CF gene, which means he is not a carrier and he is not her dad.
Hospital staff have felt bound to keep the secret from him. But when they told the mom, it came as no surprise; it rarely does.
"It is probably true in a lot of families, that daddy is not who you think it is," says Steve Scherer, a senior scientist in department of genetics at the Hospital for Sick Children.
As families gather this festive season, here is a spicy fact that mothers might be loath to dish out at the holiday table: It's now widely accepted among those who work in genetics that roughly 10 per cent of us are not fathered by the man we believe to be dad.
Geneticists have stumbled upon this phenomenon in the course of conducting large population studies and hunting for genes that cause diseases such as cystic fibrosis. They find full siblings to be half-siblings, fathers who are genetic strangers to more than one of their children and uncles who are much closer to their nieces and nephews than anyone might guess. Lumped under the heading of "pedigree errors," these so-called mis-paternities, false paternities and non-paternities are all science jargon for the unwitting number of us who are chips off someone else's block.
The proverbial postman seems to be ringing twice in everyone's neighbourhood. Non-paternity is believed to cut across all socio-economic classes and many cultures. Factor it into genealogical attempts to trace ancestry and it can snap entire branches from a family tree. Considered in light of long-held views about sexual behaviour, it exposes the myth of female monogamy and utterly shakes the assumption that women are biologically driven to single-mate bliss.
The widespread use of DNA analysis has presented science and society with all sorts of new ethical problems, and now it's pulling this naked truth out of the closet and into the courtroom. Men who call themselves "Duped Dads" are looking for legal redress to protect themselves against paternity fraud, raising questions about the definition of fatherhood. Several U.S. states are considering legislation that could exempt non-biological fathers from having to pay child support.
Even the most learned among us are grappling with the implications. Last month, the 10-per-cent non-paternity rate was cited during a science seminar for judges in Halifax.
"The judges were just shocked; they really couldn't get over how many people this would affect," Dr. Scherer said. "They kept saying things about all those poor people who might be misled -- never realizing that one of them might actually be among them!"
The notion of a woman carrying the child of someone other than her partner is older than the Christmas story itself. No geneticist believes non-paternity to be purely the product of modern immorality; they have been tripping over the infidelities of earlier generations for decades.
Cheryl Shuman, director of genetic counselling at the Hospital for Sick Children, said that 15 years ago, when genetic tests were less powerful, researchers had to draw blood from a child, his or her parents and both sets of grandparents. "Sometimes we'd get a call from the grandmother, and she'd say, 'Listen, my son, or my daughter, doesn't know that their father is not their real father. . . .' "
In the interests of maintaining family peace, Ms. Shuman said, the tests would be dismissed as "uninformative."
Over the years, the hospital has relied on the advice of lawyers and ethicists to develop policies for handling the situation. For example, its consent form now warns what a genetic test can reveal. Parents "will sometimes giggle in the waiting room when they read the paragraph about non-paternity," Ms. Shuman said. "But then we get the phone call later, forewarning us as to what we might find."
When a test disqualifies a father, "most women do express some surprise, but then there is a resignation, or an acceptance that they were kind of half anticipating this was going to happen. But then all this is followed very quickly by panic and questions as to whether or not we will betray their confidentiality."
If the case involves an expectant mother, Ms. Shuman explained, the hospital's legal obligation is clear: The developing baby is considered part of the mother and the results of the tests therefore belong to her.
After birth, the course of action is less clear, she said, but lawyers advise that the child is to be considered the patient, whose needs trump those of the parents. Since telling the father could trigger a breakup and leave the child without proper support, the hospital keeps the secret. Sometimes it can be a whopper.
In one family with four daughters, the DNA analysis was so surprising that counsellors asked the mother to explain. "It turned out that the daughters had three different fathers," said Peter Ray, a scientist at the hospital. "We cannot make any conclusions based on the family structures as they are presented to us."
In the research world, when scientists come across a father in a mismatched family, they toss the sample. If pedigree errors are not caught, Dr. Scherer said, they can wreak statistical havoc with a study: "People have made careers designing software to catch these kinds of things."
Sample mix-ups can skew results, as can an extremely rare condition discovered in 1989 in which a child inherits two copies of the same chromosome from one parent, obscuring the contribution of the other. But as the number of gene hunts and diagnostic tests has grown and grown, the leading cause of these anomalies has proved to be mistaken fatherhood.
Some peg the range at 5 to 10 per cent; others, such as Jeanette Papp of the University of California at Los Angeles, feel that 15 per cent is reasonable for the Western world, even if there is no hard evidence. "It's hard to do studies on these things for ethical reasons," says Dr. Papp, director of genotyping and sequencing in UCLA's department of human genetics. "I mean, how do you tell people what you're really looking for?"