I saw this article on the New York Times website today.
The article is not related to surrogacy, but does deal with IVF in general. My IPs did not choose to PGD test their embryos, but I know that many IPs do. After hanging around in the surrogacy world for the last couple of years, I have heard of many people, even without known genetic issues, to screen all their embryos for various common diseases and abnormalities (such as trisomies) to be sure they are only transferring embryos that will result in healthy children. I've also heard of people using PGD to determine the sex of the embryos and decide which to transfer based on that information.