Due to amniocentesis (which is unobjectionable in itself), I expect there will be increasing pressure to euthanize the developmentally disabled. Indeed, bioethics is moving beyond abortion, which it takes for granted, to infanticide ("after-birth abortion").
I expect the pressure will be due to increasing hostility towards the developmentally disabled. Parents will be publicly shamed for having developmentally disabled kids. Social disapproval will be extended to them and their kids, functioning as a deterrent to other prospective parents who flout social convention by daring to have developmentally disabled kids.
In other words, you might have parents who, left to their own devices, would bring a developmentally disabled child to term, but there will be an external disincentive in the form of peer pressure. If the power elite succeeds in secularizing law and culture, this will become a very dangerous world for the weakest, most defenseless members of society. Indeed, we're already well-advanced in that direction.