Downs is not genetic in the usual sense. It’s almost always caused by the uneven division of the ovum, as occurs more frequently as a woman ages. There is only a tiny percentage of cases that are actually genetic as we think of it.
No amount of killing off fetuses will ever eliminate it. It would have to be by a different process that we haven’t invented yet.
I know it’s the Bee. Just pointing out the error, which tends to get repeated again and again.