Designer Babies

In the mid-1990s, embryologist Jacques Cohen pioneered a promising new technique for helping infertile women have children. His technique, known as cytoplasmic transfer, was intended to "rescue" the eggs of infertile women who had undergone repeated, unsuccessful attempts at in vitro fertilization, or IVF. It involved injecting the cytoplasm found inside the eggs of a fertile donor, into the patient's eggs.

When the first baby conceived through cytoplasmic transfer was born in 1997, the press instantly hailed Cohen's technique as yet another technological miracle. But four years later, the real story has proven somewhat more complicated. Last year, Cohen and his colleagues at the Institute for Reproductive Medicine and Science of St. Barnabas, a New Jersey fertility clinic, set off alarm bells among bioethicists with the publication of a paper detailing the genetic condition of two the 17 cytoplasmic-transfer babies born through the clinic to date. The embryologists reported that they had endowed the children with extra bits of a special type of genetic material, known as mitochondrial DNA, or mtDNA, which came with the cytoplasm transferred from the donor eggs to the patient's.

That meant the resulting children had three genetic parents: mother, father, and mtDNA donor. It also meant that female children would transmit their unorthodox combination of mitochondrial DNA to their own offspring (mtDNA is passed down only through eggs), with unknown implications. In effect, Cohen had created the first bioengineered babies. As Cohen's group noted, their experiment was "The first case of human [inheritable] genetic modification resulting in normal, healthy children."

Just how normal those children will turn out to be is anybody's guess. At a recent meeting in Europe, the New Jersey researchers reported that one of the children conceived through cytoplasmic transfer has been diagnosed with "pervasive developmental disorder," a catch-all term for symptoms that range from mild delays in speech to autism. Cohen's group maintained that it is extremely unlikely that cytoplasmic transfer and the resulting mishmash of mtDNA is to blame.

But geneticists have only begun to trace the connections between mtDNA and a host of diseases ranging from strange metabolic ailments to diabetes and Lou Gehrig's disease, and some experts argued that the child's disorder may well be caused by a mismatch between the donor and mother's mtDNA. As Jim Cummins, a molecular biologist at Murdoch University in Western Australia, put it: "To deliberately create individuals with multiple mitochondrial genotypes without knowing the consequences is really a step into the dark."

Welcome to the murky world of "reprogenetics," as Princeton biologist Lee Silver has dubbed the merger between the science of genetics and the fertility industry. While much of the nation's attention has been focused on human cloning, a possibility that is still largely theoretical, a massive, uncontrolled experiment in bioengineering humans is well underway in the Wild West of American fertility clinics, as Cohen and his colleagues have demonstrated. Indeed, there has been more debate over -- and far more research into -- the implications of bioengineered corn than of bioengineered humans.

Now, many bioethicists believe that Cohen's experiment with cytoplasmic transfer was just one more small step towards a world in which eugenics is another name for making babies. Today, any couple with several thousand dollars to spare can choose the sex of their offspring, while parents who are carriers for certain genetic disorders can undergo IVF and have the resulting embryos genetically tested to ensure their children are free of disease. Tomorrow, parents may be able to enhance their offspring with designer genes. One day, the fertility industry's efforts to help couples conceive could bring society to the brink of altering the genetic heritage of the species.