An eight cell embryo ready for biopsy. Credit: The Infertility Center of St. Louis

The first baby in Britain to have been screened as an embryo for a genetic variation, called BRCA1, which greatly raises risk of breast cancer, has been born, according to recent news report. Because several members of the infant's father's family had been diagnosed with breast cancer at a young age, the parents decided to undergo IVF and screen their embryos for the mutation before implanting them.

The decision was a controversial one, raising arguments that this type of screening is one step on a slippery slope towards eugenics. Pre-implantation genetic diagnosis, as the procedure is called, has traditionally been limited to genetic disorders known to be fatal. But as the number of known disease-linked genes grows, so do the options for testing. BRCA1 raises a women's risk of developing breast cancer to about 80 percent, but does not guarantee that she will develop the disease.

The event has garnered extensive press in the UK, where in vitro fertilization is highly regulated; the governing body that oversees fertility only recently voted to allow this kind of screening. But in the US, where reproductive technologies are largely unregulated, such cases may already be occurring regularly. A fertility specialist I spoke with for a review published in the March 2007 issue of TR, said his lab had tested embryos for more than 150 diseases or risk genes, including the BRCA1 variant.

Little data exists on the rates of this type of testing in the U.S., one of the few developed countries with so little regulation. Sex-selection, for example, is not outlawed, though most fertility clinics say they consider it ethically questionable and decline such requests. Any disease or trait for which a genetic risk factor has been identified--one that predicts athletic prowess, for example--could theoretically be screened for, and the number is growing daily.