A U.S. fertility clinic is courting controversy that it is wading into the realm of "designer babies" after announcing recently that it can help expectant parents choose the genetic traits of their future children.

Fertility Institutes says it will soon offer a service to help couples select both their baby's gender and physical traits, such as eye or hair colour, using pre-implantation genetic diagnosis, or PGD.

The clinic says it has already received "half a dozen" requests for the service, which will be available to couples undergoing IVF, or in vitro fertilization.

The clinic claims it can make no guarantees as to "perfect prediction" of things such as eye or hair colour. But it has already been using PGD for gender selection and claims it has a success rate in that area of greater than 99 per cent.

PGD is already used at fertility clinics around the world for couples who have recurrent miscarriages, or who need to screen out embryos that have inherited the genes for life-threatening diseases.

In Canada, its use for gender selection is illegal under the Assisted Human Reproduction Act. That's not the case in the U.S. which has looser regulations on fertility clinics.

In 2006, a survey by the Genetics and Public Policy Center at Johns Hopkins University found that 42 per cent of 137 PGD clinics offered a gender-selection service.

The process involves fertilizing eggs in a lab. When the embryos are three days old, a single cell is removed and analyzed. If the cell has an abnormal chromosome count, the embryo is discarded. Healthy embryos are then implanted in the mother's womb.

While PGD has existed since the 1990s, the technology has now quietly progressed to the point that it can be used to create "designer babies" for hopeful parents who want to select their children's physical traits.

Dr. Jeff Steinberg, a pioneer of IVF in the 1970s who now runs the Los Angeles office of Fertility Institutes explains that his clinic started out by trying to screen out albinism and in the process, learned how to predict eye colour.

Dr. Mark Hughes, a molecular geneticist and the founder of the Genesis Genetics Institute in Detroit, where the world's first PGD was performed, says using the technology for gender selection is something his clinic "abhors."

"We developed this technology to help avoid serious inherited diseases that couples can carry," he told Canada AM.

"And hundreds of Canadians have used this technology because they know that they are at high genetic risk of cystic fibrosis or muscular dystrophy or hemophilia or whatever.

Now people are pretending that it can be used for trait selection and the truth is it can't."

Hughes notes that parents cannot select physical traits for which they don't carry the genes. So, for example, two black parents cannot ask for a blond, blue-eyed baby.

And other traits that parents might want their children to inherit, such as athleticism or beauty or intelligence, are not the result of a single gene, but multiple genes, some of which haven't even been identified.

"I would argue that if were looking to create a child through this technology with superior intelligence, you probably don't have those genes by default to give to your children," Hughes said, half-jokingly.

He also reminds that in order to take advantage of PGD, a couple would have to go through in vitro fertilization, which requires the injection of fertility drugs and uncomfortable and risky medical procedures.

"I don't care if you're a billionaire -- what kind of patient would go through the emotional and physical roller coaster of IVF so that they could have a child with freckles and a short nose?" Hughes wonders.

Steinberg told the Australian Associated Press recently that he believes that PGD technology has handed parents the ability to ensure their child is as healthy as possible and that the service his clinic now offers is just the natural extension of that.

"You can say eye colour and hair colour are not diseases, no they're not, and there is a cosmetic element to it, but we fix crooked noses all the time," Steinberg said.

"It's new, it's scary and it's not for everyone... but (people) shouldn't condemn it."