A Frisco, TX couple says they have spent six-figures to make sure their third child is a girl.

Rose and Vincent Costa, already parents of two boys and in their late 30s, say they always wanted a girl.  To make sure they got their wish, the Costas spent $100,000 for several in vitro fertilization sessions.  Though the Costas didn't have any fertility issues, the in vitro fertilization gave the couple the opportunity to screen embryos before they were implanted, a practice that is more common than people think according to Dr. Jerald Goldstein,

It's certainly much more common now than it was a few years ago.

And, as that's become more available, then obviously you can detect X or Y.

If the technology's available, and you're not actually causing harm, then it seems like a reasonable option to be able to offer to patients.

Some who have opposed such genetic manipulation regularly cite religious objections.  Ray Bohlin from Probe Ministries in Plano regularly speaks out on genetic engineering of children,

You have perfectly healthy people who are choosing a process by which you know certain embryos are going to be discarded or killed.  Is that a direction you really want to go, and are we willing to extend that for just eye color, or hair color?

The idea of genetic engineering children has been a mainstay of science-fiction, most notably in the 1997 film 'Gattaca', where genetic engineering before birth has become so commonplace that children born without eugenics are second-class citizens, known as "in-valids".