“A revolution is under way in human reproduction that is comparable in many ways to the revolution in physics that produced the atomic bomb,” wrote Peter Singer, the noted ethicist and philosopher, in the pages of TR in February 1985 (“Technology and Procreation: How Far Should We Go?”). The revolution was the new wave of fertility technology, which seven years before had resulted in the first human baby conceived outside the womb. Singer felt that in vitro fertilization and other advances, like gene therapy, might “someday give us the power to reshape the human species itself.”

Taken in itself, IVF may seem nothing more than a means of helping some infertile women become pregnant. But it opens the door to an avalanche of technologies that could be far more controversial: the freezing of human embryos for research use, the donation of an embryo from one woman to another, surrogate motherhood, sex selection, gene therapy for inherited diseases …

Not all of Singer’s predictions turned out to be accurate; genetic engineering of human traits, to name one potential technology he cited, isn’t close to happening. But his essay is a reminder of the ethical angst created by the fertility breakthroughs of the time. To ethicists such as Singer, then head of the Centre for Human Bioethics at Australia’s Monash University and now a professor at Princeton and the University of Melbourne, the dawning era of biotechnology seemed full of unknown dangers. “Should we tinker with the human gene pool?” he asked. “If so, in what way?” The new techniques, he wrote, “may even allow us to select for desirable traits as well as against undesirable ones”:

This could be done by producing several embryos, identifying their genetic characteristics, and then implanting the most desirable embryo. Eventually, it may even be possible to modify the genetic properties of an embryo before implantation to eliminate defects and build in desirable qualities.

As he was writing, doctors were preparing to use gene therapy to treat a brain disorder called Lesch-Nyhan syndrome (the attempt would be unsuccessful, it turned out). The treatment involved removing bone marrow cells from affected children, genetically altering the cells, and injecting them back into the patient. A logical next step, Singer wrote, would be to use the therapy to treat genetic defects in the womb. And if major defects could be cured, why not minor ones?

In time, we may even decide to build in positive modifications. After all, natural selection has left ample room for improving the human race. And the ethical line between eliminating defects and making positive modifications is difficult to draw. If we learn how to affect intelligence, should we stop short at eliminating mental deficiency? If we eliminate abnormally depressive personalities, would it be wrong to try to produce people who tend to be a little more cheerful than most of us are now? If we eliminate tendencies toward criminal violence, might we not build just a little more kindness into the human constitution?

Singer thought we needed a new system of ethics to deal with our new capabilities. What future human beings might do with technology was anybody’s guess, but in his mind it was better to think about all the possibilities in advance. (Some countries have tried to limit those possibilities by law: Germany and Norway ban egg donation, while France and Italy deny IVF to single women and gay couples.) Singer saw no problem with a couple using an egg donor if the woman had a genetic defect. But who defined what a “defect” was?

What if the defect is very minor? What if there is no defect at all, but the couple wants a donor egg or sperm from a male or female friend whose intelligence or beauty they consider superior to their own? A California sperm bank is already offering selected women the sperm of Nobel Prize–winning scientists.

Singer noted that some people feared a darker outcome. If we could make ourselves smarter or more beautiful, they mused, a government might be just as capable of using genetic modifications to make us docile. Here, at least, he felt we had nothing to worry about.

If we have succeeded in keeping our freedom in the age of television, snooping devices, and computers, we should be able to cling to it when we have the means to manipulate genetic traits as well. The technical ability to suppress liberty has been with us for a long time. It is our determination to prevent our rulers from exercising this ability that has kept us free.

Timothy Maher is Technology Review’s assistant managing editor.