I just read through this thread:
Surprisingly, none of the Jewish posters have weighed in. Too bad, because we could add another perspective.
Thanks to a relatively limited gene pool, certain nasty genetic diseases are more common among Jews. One of the earliest to be identified was Tay Sachs disease - a truly nasty disorder in which a child seems normal at birth, but goes downhill at around 6 months and dies before the age of 5. More info here: http://en.wikipedia.org/wiki/Tay%E2%80%93Sachs_disease. A carrier of the disease will be perfectly normal, but if 2 carriers have a child, there is a 25% that the child will have the disease.
One of the reasons that Tay Sachs is so well-known in the Jewish community, aside from its nastiness, is that there are widespread screening programs that started around 1971. By widespread, I mean that every Jewish teen is told to go for testing, and in very Orthodox circles, there is an organization that ensures that matchmakers don't set up 2 carriers.
I was raised hearing about this from the time that I was a kid, so I forget somethings that it's a novel idea for some. My parents actually got tested when I was newborn (I was born in 1971) - and they were told that they were carriers. It was a moment of terror for them because I was too young to show symptoms, and yet there was a 1 in 4 chance that I could have a fatal disease. With my sister, they had an amnio. My mom described it as stressful, since she hid the pregnancy until receiving the results, but less stressful that worrying about a baby having it.
I haven't seen much moral debate about this in the community. It's considered obvious that the only way to deal with the disease is by preventing it through screening. Obviously, there are no guarantees in life, and a child who doesn't have Tay Sachs could still have any number of other problems, but if you could prevent a child from suffering with a horrible disease - why wouldn't you? Thanks to the screening, cases of Tay Sachs have become exceeding rare in the Jewish community.
I've seen a bit more moral debate on the question of "what do you do with the information"? The ultra-Orthodox organization Dor Yeshorim doesn't tell those who are tested what their carrier status is, only whether they are genetically compatible with a potential mate. They have concerns that people would avoid testing due to stigma. That's truly unfortunate, because being a carrier in no way affects your life unless you happen to fall in love with another carrier. It just means that you need to tell your kids to get tested themselves.
One option that exists today that my parents didn't have is pre-implantation diagnosis. Yes, it is more expensive and involves more than having an amnio, but it also avoids the possibilities of a second trimester abortion.
Righteous Rasha has a post on Dor Yeshorim, the ultra-Orthodox anonymous testing organization. I agree that anonymous testing is far from ideal, but suppose that an imperfect option that at least prevents genetic diseases is worthwhile if the stigma would otherwise allow tragedies to occur.