The following article appears in the March/April 2007 issue of Technology Review.
A 38-year-old woman with fertility problems has three sons but wants a daughter to round out the family. She uses in vitro fertilization (IVF) to conceive and asks her doctors to transfer only female embryos; the male embryos are destroyed. Is this use of reproductive technology acceptable? What if a couple with a family history of diabetes wants to use IVF to select an embryo without a particular gene linked to diabetes risk? If afflicted family members largely have the disease under control, are the prospective parents justified in choosing in vitro fertilization so that they can bear a child with a lower chance of developing it at all?
Such questions are becoming more common as preimplantation genetic diagnosis (PGD)–testing performed after an egg is fertilized in vitro but before the resulting embryo is transferred to the womb–makes it possible for some prospective parents to select specific embryos before a pregnancy begins. Originally developed more than a decade ago to identify the relatively small number of embryos at high risk for serious or fatal genetic diseases, such as Tay-Sachs, the technology now encompasses genetic tests for a growing number of illnesses, including some that are not necessarily fatal. And these tests are available to more and more parents as the popularity of in vitro fertilization skyrockets; approximately 50,000 babies are born through IVF in the United States every year.
All this heightens the ethical concerns that have plagued PGD from the start. As more genes associated with the likelihood of disease are uncovered, the possibility of a truly preventive medicine is within the grasp of many parents. But with that possibility come risks. How well will any one test deliver on its promise of a healthy child? Will parents feel obligated to use genetic testing without adequately understanding its benefits? What kinds of genetic tests will parents want? Recent findings suggest that an increasing number of parents using IVF are choosing embryos according to sex, and it’s possible to imagine them one day choosing embryos based on other nonmedical traits, such as hair color, height, or IQ.
Preimplantation genetic testing is available only to those who opt for IVF–which now generally means people with fertility problems or a family history of a fatal genetic illness. Though IVF is gaining in popularity, it remains an expensive and often difficult procedure. But the grounds for choosing it are changing: some people, for example, are now using it to select embryos without genes linked to particular cancers–even if the correlation is fairly weak. If parents increasingly choose IVF because it will offer them the opportunity to tailor their children’s genetic traits, will the economic division of society become even deeper–separating those who can afford IVF (clinics in the United States generally charge between $6,000 and $16,000) from those who cannot?