Genetic screening and using genetic manipulation isn't a new idea. It has been around for 10,000 years or so. This is just the time that humans have used it. Nature has always used it. We humans just sped up the process. We would cross breed crops so that they would withstand drier seasons, mate certain cattle to produce more milk or meat. As it is used today, the main difference is that we can do it in a laboratory on the level of the actual genes.
If you look at someone's genes to make a decision then you are committing a more modern version of racism. This is one of those things that looks good on paper, but when it hits close to home it is not such a good idea. What would you do if you go to get medical insurance and because of the screening you find out that you child has a disease and won't live past 20? Knowing this doesn't change the fact but there are times that ignorance is bliss.
There have been many instances in the near past that genetic screening has been used. Of course the bad side of it is the one that we always remember. The Nazi's are the first ones that spring to mind. They used it both to recruit for their army and as the way that they decided which people didn't deserve to live.
It wasn't just the Nazi's that used this. In America, the wanna be science of Eugenics did the same thing. They advocated the sterilization of people that were mentally handicapped. This would take them out of the gene pool, and in theory make the population better. This is an idea that seems insane in itself, and most people would not stand for it. The scary part is, we are heading in that direction again but this time we are using "real" science to back the same ideas.
If you look at it from an unbiased point of view (which is almost impossible), there are good things that can come from genetic screening. It could help with military recruitment, finding people that have a genetic code that works for that kind of violence. You could use it for teachers for the same reason, obviously for opposite reasons though.
From the business point of view. Insurance companies would better know who to insure. It would help the medical field with diagnosis. In general you could better the human race. It has been written about for decades in science fiction. If it is put into use, you will find it is used for the "bad" reasons more than the "good".
I don't think that it is a question of if it will be used. I think that it is a question of when it will become widespread. We have been heading in that direction for years. It has just been sped up in the last few, at the same time media coverage has put it into the living rooms of America.