Would you be able to to live `till the end of his life and take care of him?
Who will take care of him if you die before him?
That kid will curse you all for being born and exist in this world as he grow up, especially if he has a serious disorder preventing him to have a normal life or if he has no legs, arms or something like that. He will curse his parents and to the whole world as much as he sees healthy people around him. Who wants to be a cripple?
So, if the child has defects, parents should be able to do abortion even if the mother is 9 months old pregnant.