“This is a potentially disruptive technology, one that can change the social structure and order,” says David Adamson, president-elect of the American Society for Reproductive Medicine and director of a private fertility clinic in northern California. “It will move us toward a preventive approach to medicine and could change our approach to reproduction.”
Tests are already available for genetic variants associated with a thousand conditions, including deadly childhood illnesses and adult-onset cancers, and more genes associated with disease risk are being discovered every day. Any such gene could be a target of PGD. Santiago Munné, director of Reprogenetics, a genetics laboratory headquartered in Livingston, NJ, says his lab has tested embryos for more than 150 diseases or risk genes–most recently for a gene variant known as BRCA1, which raises the risk of breast cancer.
Little data yet exists on the use of preimplantation genetic tests. But late last year, the Genetics and Public Policy Center at Johns Hopkins University released a report in the journal Fertility and Sterility presenting some of the first statistics on the use of PGD nationwide. “We wanted to get a sense of how much PGD was being done, and why,” says Susannah Baruch, the center’s director of reproductive genetics and lead author of the report. “Without solid data, it’s difficult to analyze outcomes for PGD babies or to help prospective parents make decisions about whether to pursue PGD.”
The researchers surveyed all the fertility clinics in the United States that offer IVF, asking questions about the types of preimplantation tests they administer, how they make ethical decisions, and how they think testing should be regulated. About half of those clinics responded. According to the survey, screening for chromosomal abnormalities that can lead to implantation failure or miscarriage, or for disorders linked to chromosome duplication or deletion (such as Down’s syndrome), represents two-thirds of all PGD testing. Tests for genetic diseases such as cystic fibrosis account for another 12 percent. Forty-three percent of clinics said they had received requests for PGD that they felt raised ethical questions; most of these were from parents who wanted to select the sex of a child for nonmedical reasons. The survey found that this use of PGD is fairly common: almost one in ten tests was for nonmedical sex selection, a service offered by 42 percent of clinics.
Since it is the only PGD test that is often administered without medical justification, sex selection is especially contentious; some fertility clinics will not offer it, and some ethicists say that nonmedical sex selection opens the door to other types of nonmedical testing. But other people argue that biological enhancement through genetic screening is not so alarming, or at least not so different from other types of advantages that are already enjoyed by a certain privileged sector of the population. “I don’t think testing for freckles or blond hair or musical aptitude is a morally bad thing to do,” says Arthur Caplan, director of the Center for Bioethics at the University of Pennsylvania. “I think parents will want to do it, so I think this will expand rapidly.”