It's on a spectrum. Some are utterly unable to take care of themselves. By going forth with a pregnancy, you take on the risk that outcome can be far worse than

It's on a spectrum. Some are utterly unable to take care of themselves. By going forth with a pregnancy, you take on the risk that outcome can be far worse than exemplified. Chromosomal deletion is one possibility. No one wants to take care of a vegetable, let alone roll the dice on a "milder" case of downs.