WHEN YOU TRY to win a new war with the weapons that won the last one, you usually lose. That's a clich頯f military history, but somehow we forget that it applies to politics, too. In the battle now shaping over stem-cell research, leaders on both sides appear to be falling victim to this dictum. Adopting the battle-blunted weapons of the pro-choice vs. right-to-life campaign, they're guaranteeing that the critical new issues raised by the new field of experiment won't get answered.
So what are stem cells? When an ovum starts dividing after fertilization (skip the next couple paragraphs if you're up to speed on developmental biology), the first few generations of daughter cells are pretty much identical to their mother and to each other. But soon—no one yet knows just how soon, but within half a dozen doublings in number—daughter cells begin to diverge in character, driven by a sequence of chemical switches programmed in their genes.
Early generations of fetal cells are "pluripotent," meaning they can be directed toward any bodily purpose, but once a genetic signal nudges a cell down the path toward, say, liverdom, any potential for nervehood is pretty much foreclosed. That's not all: Once a predestined final functional state is reached, a molecular counter begins turning over in most cells; after they register a preset number of clicks—one for each further doubling—they die. After enough of them do, so do we.
"But ah," says Science, a gleam in its eye, "what if we could turn the molecular counter back? Or at least replace the suicidal cells with juicy young ones devoted to the same bodily function, their odometers still at zero? No more senile dementia, no more liver failure—no more liver spots! With access to cells like that, we could—dare I say it?—become immortal."
This line of argument is not new. It was trotted out most recently in 1989, in the abbreviated reign of George I, though that time around the cells in question were being extracted from dead fetuses. Promising or not—and the biomedical establishment lined up almost unanimously in favor—federal support for this line of research was vetoed by the president, primarily because of vehement opposition to it by anti-abortion activists.
The "ban" didn't last long. Bill Clinton reversed it as soon as he stepped into the Oval Office. Unfortunately, federal funding or not, the technique hasn't fulfilled its advocates' therapeutic hopes. But it did lead, indirectly, to the discovery that cells extracted from embryos much earlier in the developmental process can be teased into following the career path scientists want them to. Even better, the cells can be extracted from spare fertilized eggs sitting idly in fertility clinics after their donors have hit the baby jackpot. These "useless" eggs are sooner or later going to be discarded; surely no one could reasonably object to putting them to good use instead?
I hate to say it, but in this fight it's the illiberal bad guys who hold the moral high ground. At least they're consistent; if a fertilized human egg is a human being, deliberately destroying it is murder. Trouble is, their intransigence has allowed their opponents to cast the whole stem-cell research issue in pro- and anti-abortion terms, while, willfully or not, ignoring the far deeper political and philosophic issues posed.
It's not likely that this round of research will revolutionize therapeutics any more than the last round did: Embryonic development still holds too many mysteries, and apoptosis—the process of programmed cell death—shrouds even more. But therapeutic applications are an easy sell, to both Congress and the public, and with the Right to Life movement in opposition, would-be researchers aren't likely to be called on to justify what they propose to do in any other context.
There is another context, however. What stem-cell researchers are proposing to do, avowedly or not, is to steer a portion of the human genetic heritage— itself a miniscule substrand of the heritage of life—in a new direction entirely. An ovum belongs, legally and morally, to one specific woman. But do pluripotent cells derived from that ovum, with her explicit permission or not, belong to her?
If not, to whom do they belong? And if Science, licking its dry lips in anticipation, finds a way to persuade those cells to maintain their youthful lack of definition and to reproduce—i.e., live— indefinitely, in whose interest will it be? In theory, perhaps, humankind's in general; in practice, the person who owns the dish they grow in: a thread of human life carrying the full potential to unfold into a human, reproducing forever in a test tube, to be tweaked toward any purpose its possessor may will.
THE RATHER GOTHIC tone of the last paragraph is intentional. Research into the mysteries of cellular differentiation and death will continue, with federal funding or not. The question before the public is, or should be: Under what conditions, what limits, what philosophic or moral constraints will such research take place? Once you begin to think about this question, the issues raised by Steven Spielberg's A.I. seem trivial. Never mind exploring the dilemmas of future artificial beings; we've got enough on our plate trying to make sense of the ones facing us meat-based entities right now.