Guest blogger Elizabeth Kelly: What if you could choose whether to have a boy or girl? What if you could pick your child's hair color, eye color, and shade of skin? Well, now you can.

According to the website for a Los Angeles clinic called Fertility Institutes, "for the first time ever, patients having genetic screening for abnormal chromosome conditions in their embryos will be able to elect expanded testing that can greatly increase the odds of achieving a healthy pregnancy with a preselected choice of gender, eye color, hair color and complexion."

Sound creepy? Not according to the medical director of the clinic, Dr. Jeffrey Steinberg, who told the Wall Street Journal "This is cosmetic medicine."

Preimplantation genetic diagnosis (PGD) is a process that's typically used to test embryos for genetic diseases such as cystic fibrosis. However, it's already being used in some clinics, including Fertility Institutes, to help women undergoing in vitro fertilization choose the sex of their children by sorting out only the male or female embryos for transfer.

In some cases, screening embryos for a particular sex is used to avoid fatal gender-linked diseases such as Duchenne muscular dystrophy, which occurs almost exclusively in males. But most of the time, it's used for "family balancing" -- and Fertility Institutes even offers it to first-time parents.

And now Fertility Institutes promises to add physical trait selection to the PGD services it offers. To some degree, prospective parents using donor sperm or eggs in conjunction with fertility treatment are already shopping for their dream babies by selecting donors who are Asian or redheaded or tall like them ... or, in some cases, who are particularly smart or attractive or athletic -- maybe even significantly smarter or more attractive or more athletic than the parents-to-be themselves.

But when we select and discard embryos solely on the basis of their traits or gender, we've taken it to a whole new level. What do we give up when we demand this kind of control? Most of all, we give up our humanity, our ability to open ourselves up to the surprises and discoveries the universe, and in turn, our children, have to offer us. And that, if you ask me, is half the joy of parenthood.