From then until the repeal of Boni-face’s decree in 1556, those who dared conduct studies in human anatomy had to work surreptitiously—the most famous example being that of the anatomist Andreas Vesalius, who would visit places of execution where criminals had been left hanging overnight and carry out secret dissections by torchlight. His famous book of 1543, On the Structure of the Human Body, provided the first reliable information on human anatomy ever compiled. Much persecuted for impiety, Vesalius wandered from country to country and eventually, to escape the Inquisition, undertook a pilgrimage to Jerusalem, where he died.

Through his studies of heavenly bodies the Polish astronomer and mathematician Nicolaus Copernicus came to believe that the theory that the Earth was the center of the universe—an essential part of Christian dogma—was wrong. For twenty years he worked on a book he called On the Revolution of the Celestial Orbs, but did not publish it—not out of fear of religious persecution, but because he mistrusted his data. (He knew that something was wrong with his theory, but it remained for a later astronomer, Johannes Kepler, to show that the planets move in elliptical orbits, not the circular ones of Copernicus’s hypothesis.) Eventually, in 1542, less than a year from the end of his life, Copernicus did allow his book to be published. It caused no great theological stir at the time, apparently because both the Catholic and Protestant churches looked upon it as absurd, rather than as ideologically dangerous.

But Kepler’s work, and then that of Galileo Galilei in the early seventeenth century, was much more threatening. Galileo, in 1615, went so far as to say that if one took the Bible literally on astronomical matters, “one might fall into error.” This embroiled him in decades of controversy with the fathers of the Church and finally, after a trial by the Inquisition that found him guilty of heresy and sentenced him to prison, he recanted his belief in the movement of the Earth around the Sun and was set free. He was then seventy years old, and in his remaining years said nothing more on the subject of the movements of the planets.

What must have been on Galileo’s mind at his trial was the fate of Gior-dano Bruno, an Italian philosopher and supporter of the Copernican theories, who postulated that the universe was infinite and contained an infinity of worlds, and who was imprisoned by the Inquisition from 1593 to 1600 and finally burned at the stake, defiant to the end. He was, I suppose, the last scientific thinker to be martyred for disagreeing with official theological belief. Burning at the stake has gone out of fashion in modern times. Scientists and religious leaders still often find themselves in conflict these days, but it is science itself, not the scientists, that the advocates of faith would like to burn.

This brings me, of course, to the great stem-cell controversy that has occupied so much public attention recently. I am writing this during the summer of 2001, but I suspect that the uproar will still be going on when you see it.

The briefest of summaries, since surely you all know the basic story by now: In 1998 Dr. James A. Thomson, a University of Wisconsin biologist, announced that he had been able to extract “stem cells,” capable of being grown into any sort of bodily cell or tissue, from human embryos. The possibility thus arose that tissue derived from embryonic stem cells could serve to rebuild a damaged heart or a failing liver or a deteriorating pancreas, replace neurons injured by a stroke or a neurological disease, restore the skin of a burn victim, reconstruct an injured spine, and so on—a wide range of miraculous-sounding remedies for almost every bodily ill.

The big problem, though, is that embryonic stem cells come from embryos, and in the United States of the twenty-first century, embryos are regarded by a goodly percentage of the population as sacred and untouchable. An embryo used for stem-cell work is thereby prevented from completing the process of cell division and ultimately developing into a human being; thus, technically speaking, stem-cell work is a kind of abortion. And so stem cells hit the front pages.

Abortion on demand has been legal in the U.S. for decades, despite powerful religious opposition. Abortion is not something that anyone would lightly undertake, but there are those—a majority of citizens, I think—who believe that it is sometimes justifiable to abort an unborn child and that abortion should be available, as a matter of individual choice, to those who wish to take advantage of it. Others feel that human life is the gift of God, and that gift must never be rejected. The politicization of the abortion issue is reflected in its velvet-glove semantics: one group calls itself “pro-choice,” not “pro-abortion,” and the other uses the label “pro-life” instead of “anti-abortion.”

If it were only a matter of private choice, stem-cell research would now be marching vigorously ahead in the United States. The big problem is that most modern scientific research is carried out with the help of government money. Once taxpayer dollars start to be spent on work that involves the destruction of embryos, members of the pro-life faction might quite reasonably object that they are being made unwilling contributors to research they abhor.

In 1996—two years before the first successful stem-cell experiments—Congress banned the use of federal funds for all kinds of embryo research. In January, 1999, the Clinton Administration ruled that stem-cell work did not fall under this ban, and three laboratories promptly applied for and received permits to proceed with government-funded studies. But George W. Bush, soon after his inauguration, put a hold on further expansion of such work pending a full review of the moral issues involved.

What he meant, of course, was the political issues involved. The heart of his political support came from conservatives, and many conservatives—though not, I assure you, all of them—tend to take “pro-life” positions. President Bush wanted to see where his political base stood on the issue before announcing the new administration’s policy.

He promptly got conflicting and confusing advice. Catholic leaders, on up to the Pope (not an American citizen), called for a ban on all stem-cell work, whether publicly or privately funded. So did many Protestant churchmen, even the leaders of the “pro-choice” United Methodist Church. But from Nancy Reagan, not ordinarily considered a spokes-man for liberal causes, came a plea for continued research. She saw it as offering hope for victims of Alzheimer’s disease, of whom her husband, the former president, is one. Two conservative anti-abortion Senators, Orrin Hatch of Utah and Bill Frist of Tennessee, also announced their support for government funding of embryonic stem-cell research, pointing out that work that could help people afflicted with devastating diseases cannot be called anything other than “pro-life.”

After weighing all the pros and cons, President Bush finally spoke to the nation last August. His speech acknowledged the importance of allowing the free play of scientific thought, but also noted that many Americans see stem-cell work as abortion and therefore oppose it. In the end he offered a Solomonic decision: stem-cell work now under way could continue with federal support, but his administration would not license any expansion of the research. And there, I think, the matter will rest for the time being.

Some points to consider, as we go forward:

1) If ongoing embryonic stem-cell research actually does produce the miracle cures that have been suggested, overwhelming public pressure to expand stem-cell studies will sweep all political opposition aside, abortion issue or no.

2) The embryos being used are the surplus by-products of attempts at inducing in vitro pregnancies for otherwise infertile couples. Fertility clinics create more embryos per couple than are needed, implant the healthiest, and the rest are either destroyed or allowed to expire, except for the few that are contributed to medical research or donated to other couples. Hundreds of thousands of embryos have perished this way, quite legally. If prohibitions on stem-cell research go into effect, hardly any of these embryos will ever grow to full development and all of them will be pointlessly lost to science. While we cherish and preserve the rights of embryos that are destined to perish no matter what, real living people will go on bearing the burden of severe bodily afflictions. The absurdity of throwing embryos away rather than using them in stem-cell research will eventually make itself felt. Nor are embryonic cells the only useful kind. Non-controversial adult stem-cells may prove just as valuable.

3) Stem-cell work will proceed in other countries that lack our atavistic fear of Things That Man Was Not Meant To Do. It’s legal right now in Great Britain, Sweden, Israel, and Japan. Research is going on in those places at this moment. Some American stem-cell scientists, such as Roger Pederson of California, are packing up and leaving for England. If stem-cell research ever does deliver on its promise while coming under some sort of ban in our country, American patients may have to go overseas to benefit from it, and only the wealthiest will be able to. This is sure to stir political storms here.

The campaign against embryonic stem-cell research makes me wonder whether the century we are entering will be the bold, innovative, shining one promised us by so much science fiction, or the dark, cramped, medieval one Robert A. Heinlein forecast in his Future History stories. But I take heart from the fact that the worst-case scenario was avoided: the anti-science faction was not able to bring about a complete ban on stem-cell work, even with the “pro-life” George W. Bush in the White House. The work will proceed, albeit hampered somewhat by political opposition, but moving on all the same toward an exploration of the potentials of this startling new technology. Any sign of real progress toward real benefits will make it unstoppable. Meanwhile, our stem-cell researchers will not be driven underground, as could easily have happened, or forced to go overseas. Though scientists can no longer be burned at the stake for their ideas, a whole branch of science nearly was, just now, in this country, and that has been avoided. It will be interesting to see what happens next.