Biologists have been rather silent on the subject of human cloning. Some others would accuse us, as they have with predictable regularity in the recent past, of insensitivity to the societal consequences of our research. If not insensitivity, then moral obtuseness, and if not that, then arrogance—an accusation that can never be disproved.
The truth is that most of us have remained quiet for quite another reason. Most of us regard reproductive cloning—a procedure used to produce an entire new organism from one cell of an adult—as a technology riddled with problems. Why should we waste time agonizing about something that is far removed from practical utility, and may forever remain so?
The nature and magnitude of the problems were suggested by the Scottish scientist Ian Wilmut's initial report, five years ago, on the cloning of Dolly the sheep. Dolly represented one success among 277 attempts to produce a viable, healthy newborn. Most attempts at cloning other animal species—to date cloning has succeeded with sheep, mice, cattle, goats, cats, and pigs—have not fared much better.
Even the successes come with problems. The placentas of cloned fetuses are routinely two or three times larger than normal. The offspring are usually larger than normal as well. Several months after birth one group of cloned mice weighed 72 percent more than mice created through normal reproduction. In many species cloned fetuses must be delivered by cesarean section because of their size. This abnormality, the reasons for which no one understands, is so common that it now has its own name—Large Offspring Syndrome. Dolly (who was of normal size at birth) was briefly overweight in her young years and suffers from early-onset arthritis of unknown cause. Two recent reports indicate that cloned mice suffer early-onset obesity and early death.