Actually they still will exist as recessive genes it will not affect the carrier. There isn't a mechanism in what determines if they will be passed on or not and as it doesnt affect their ability to breed they will be passed on. Most likely they will still be around in the same ratio.
Here is the line that I have drawn as on this issue presenting my views:
Screening of embryo's for genetic diseases and subsequently aborting them, with a list of internationally recognised genetic diseases, with the parents told if the child is likely to get that disease or not, with the parents not told any other characteristics.
If they want an abortion fine, but it must be done without knowledge of their babies genes. Which is unfortunate as it means that abortions can be determined on sex, but that is unavoidable.
That is as far as it goes, and the genetic engineering of humans (aborting those with disease because they have them can be seen as an attempt to destroy the gene).
That is my opinion feel free to support or argue it.