It has started, from the first baby to be born without the breast cancer gene to screening for autism, science is reaching up the birth canal and performing it's miracles. I don't think science should have any morality, it's not the business of scientists, and more often than not morality can stop science in it's tracks (ie stem cell research), but is autism or Downes syndrome or similar non-life threatening conditions sufficient reason to deny someone a chance at life? Dirac (above) is a good example.
(btw Prof. S. Baron-Cohen is not Borat!!)
Personally, testing should always be there. Always. Because even if the parents won't abort a child with Downs Syndrome, or Autism, or what have you, having a child with these handicaps is a very expensive endeavor, so knowing ahead of time could help prepare for that.
Also, as far as abortion goes, one has to remember that for all the people who would abort a child with these conditions, there are many who won't. Unless its mandated by the government (which I would find heinous and unjustifiable), then not everyone will do it, and so it won't be eugenics (which, if I remember correctly, has to be a group/national event/behavior. Single incidents wouldn't necessarily count, just like how bunches of murderers acting independently aren't convicted of acts of genocide....