A summer of political biology

David Baltimore

This was the summer when politics hit biology. In earlier years, the research community successfully countered such attempts, but this summer the politicians were determined to have their say. The scientific issues at stake were two: stem cells and cloning. They entail quite separate processes but they do interact. Let’s start with stem cells.

The phrase stem cells was coined long ago for cells that both renew themselves and give rise to a variety of progeny cells. The first were ones that can develop into blood cells. Then stem cells of skin and nerve and other tissues were found. These are “adult stem cells,” and in each case the specialized cells that can be derived from them are limited to one organ. However, certain cells derived from early embryos have the potential to make all the different cells of the embryo—they are known as embryonic stem cells. These cells have excited the politicians because of the need to derive them from embryos. Their potential value is that it might be possible to control their development so that they become a source of cells to be used therapeutically anywhere in the body, say for treating Parkinson’s disease or diabetes.

Only a few years ago scientists learned how to derive human embryonic stem cells. As a source, they mainly used embryos derived in vitro, made by mixing sperm and egg in the laboratory and allowing fertilization to occur. Thus, these embryos have never been inside a person and can only grow into a tiny ball of cells. If implanted into a woman, however, they can grow into a human being, and couples use this form of reproductive assistance for some types of infertility. Thus many embryos are made and stored frozen, and many of these are ultimately discarded after the couple has the children they want. This provides a ready source of starting material for making embryonic stem cell lines.

Cloning is shorthand for deriving a fertilized egg by killing the egg’s own nucleus and then implanting into the egg the nucleus from an adult cell. An embryo derived from such a union is genetically identical to the adult who donated the nucleus and thus a clone of that adult. The idea of human clones has produced outrage among politicians and the public, even though no one has ever made such a clone and in actuality identical twins are clones in just this sense. If the method was safe, and it isn’t, it might be valuable to couples with certain types of infertility or inherited-genetic-disease issues.

Where cloning and embryonic stem cells interact is when embryos derived by cloning are used for making stem cells. There is good reason to want to do this—the stem cells would be the perfect source of organs for the adult who donated the original nucleus, because there would be no danger of immune rejection of the cells by the recipient. This is called therapeutic cloning to differentiate it from reproductive cloning, which might be used to make a whole person by cloning.

I am not aware of any work today at Caltech involving human embryonic stem cells, or of any attempts at human cloning. However, the issues are ones that concern all biologists because of a common interest in seeing that new capabilities reach the public as new therapies.

With that background, we can describe the events of the summer. Congress first got into the cloning issue. The public seemed so incensed by the idea of cloning that the House passed a bill banning it. However, the bill was drafted by absolutists who lumped therapeutic cloning and reproductive cloning together in the ban. The Senate has not acted and the slim Democratic majority may be reluctant to act, so possibly no bill will come to the president for signature. If it comes, he seems sure to sign it. Losing the opportunity to make embryos to order is no problem at the moment, but putting a ban into law would make reversing it in the future very difficult.

The president—who was responding to calls, mainly from religious groups and conservative anti-abortionists, to ban the research—took on the stem cell issue. He agonized publicly over his decision for weeks, listened to many opinions, including that of the Pope, and announced his decision in prime time on television. He gave a surprisingly learned discourse on the issues before making a Solomonic decision to allow the government to fund work on cells that already exist, but not the derivation or study of new stem cell lines. He did not listen to those in opposition who argued that adult stem cells might be able to replace embryonic ones.

Predictably, the conservatives argued that his decision was immoral, and the liberals argued that it was insufficient. Although I think that limiting research in this way is bad, I believe that Bush’s decision was realistic and is not the last word. If the research community can show that there is actual as opposed to theoretical benefit to be derived from human stem cells, but that the limiting factor is the need for new cell lines, I would think that Bush—or the next president—and Congress would be under enormous pressure from patients and their advocates to relax the prohibitions.

So this has been a momentous summer for biomedical research. In the 1970s, when recombinant DNA research was first invented, there was a push for legislation to limit the purview of the work or even to ban it. The research community fought these efforts successfully and argued that it could police itself. The issues were mainly about safety, so the moral considerations in the debates were muted. This summer morality has been the key issue. Even in the cloning discussions, where safety is a huge concern (in animals, cloning produces mainly poorly formed offspring), the moral issues have been the main ones. We still don’t have signed legislation, and maybe we can avoid it, but there is no question that the research community has now developed capabilities that many people consider inappropriate human activities. People’s moral decisions change over time, and practical considerations often outweigh moral ones when a new technology provides proven benefits. So I expect this to be a changing landscape. But as physicists discovered years ago, powerful sciences develop controversial capabilities. Now, the biological research community—never mind university administrators—is going to have to take an ever-more-public role to explain and defend their proposed activities.
•