Fearing the potential effects of creating genetically modified babies, the Food and Drug Administration (FDA) introduced a prohibition in 2001 on a relatively new in vitro fertilization procedure known as cytoplasmic transfer, which had already resulted in the birth of an estimated 30 children worldwide. What precisely were the FDA’s concerns? The healthy babies born of this technique all had genetic material from three separate individuals, two women and one man. Today, a private fertility clinic in New Jersey is quietly investigating the 17 designer babies it helped create using the procedure before the FDA ban went into effect, The Independent reports, in order to learn more about the long-term health effects.

Cytoplasmic transfer involves transferring part of one woman's egg into another's. Embryologists use the healthy portion of a donor egg (the cytoplasm) to supplement the defective portion of an infertile mother’s egg. Essentially, they take two eggs and make one good egg. Once the good egg is fertilized, the resulting embryo is supposed to contain nuclear DNA (99 percent of a cell’s genetic material) from the mother and father, and mitochondrial DNA (less than one percent of a cell’s genetic material) from the egg donor. However, a small amount of unforeseen genetic overlap occurs. The children who have been produced by this method actually have extra bits of mitochondrial DNA, or mtDNA, from both women.

Having inherited extra genes, these children have incorporated them into their germline — the genetic material they will eventually pass onto their own children. In effect, then, the embryologists who used this technique to create these children have altered the human germline and meddled with the structure of our species.

At the time, the embryologist pioneers worked at the Institute for Reproductive Medicine and Science (IRMS) of Saint Barnabas Medical Center in New Jersey, where the very first baby conceived through cytoplasmic transfer was born 17 years ago in 1997. Until now, the total 17 children who were conceived through this technique had not been checked for any long-term health problems. Yet, at a medical conference in 2002, the embryologists reported one of the children had been diagnosed with "pervasive developmental disorder," a term for symptoms ranging from mild delays to autism, though they maintained the disorder was not the result of the mtDNA.

Earlier this year, IRMS began its long-term study of the 17 children, according to The Independent, though so far it has not released any details. Jacques Cohen, one of the four embryologists who pioneered cytoplasmic transfer, told the Independent the follow-up study is being led by Dr. Serena Chen, a fertility specialist at the IRMS. “Because the research team members accepted different positions elsewhere, no follow-up was conducted until this year,” Cohen told The Independent in an email, adding, “The current follow-up study is ongoing and results will be made available in a medical journal.”

Seemingly, once the results are published or possibly even before then, the FDA will once again rule on whether to permit this controversial procedure. Meanwhile, in Britain, the wheels are already spinning. Legislation to legalize a similar technique called mitochondrial donation is before Parliament, which is expected to rule on the issue shortly. Like cytoplasmic transfer, the procedure will result in IVF babies with genetic material from three people. If legislation is passed, then, the first British genetically modified baby, who carries DNA from three people, could be born as early as next year.