Supporters of the Clinton administration's new rules permitting federally funded research on embryonic stem cells have hailed the changes as a victory for science. But the "science" that some offer is outdated, discredited, and even dangerous.
Stem cells are typically taken from fetuses killed by abortion; others are obtained by destroying extra embryos left over from in vitro fertilization. Hence stem-cell research once again raises all the moral questions raised by abortion.
And once again, supporters claim the mantle of reason and science. In a recent column, Michael Kinsley dismisses moral objections as based on mere "faith." By contrast, he writes, the "voice of reason" reveals that humans evolved originally from what was not human-and that, in a sense, we still do. In the development of the individual, Mr. Kinsley explains, "something similar" to evolution takes place, namely, "that we each start out as something less than human, that the transformation takes place gradually."
This is a restatement of the old principle that "ontogeny recapitulates phylogeny," the idea that the human embryo replays the steps of evolution. Nineteenth-century German biologist Ernst Haeckel, who coined the phrase, offered the now familiar illustration of embryos lined up side by side-fish, reptile, bird, human.
The trouble is, the illustration was faked. His contemporaries charged Haeckel with fraud, and even today scientists note that he doctored his drawings to make the embryos appear more similar than they really are. In 1997, Science quoted a British embryologist calling Haeckel's drawings "one of the most famous fakes in biology."
Yet the illustration still appears in most biology textbooks and, as a result, one sometimes hears the idea of recapitulation invoked explicitly to justify abortion. ("After all, at that stage it's equivalent to a fish or a reptile"-an argument Haeckel himself used.) More commonly, the same idea appears in the fuzzy notion that at early stages the embryo is not fully human. Mr. Kinsley acknowledges that recapitulation has been debunked; but he still offers the fuzzy, folk version as support for stem-cell research.
The controversy over recapitulation is retold in Jonathan Wells's forthcoming Icons of Evolution, along with stories of several other well-known evidences for evolution that have been discredited. For example, everyone has seen illustrations of the evolutionary "tree of life," showing how all living things supposedly arose from an original amoeba-like ancestor. There's only one problem: The fossil evidence contradicts the tree pattern.
In the fossil record, all the major groups of animals appear at about the same time-with no fossil evidence of common ancestry. This sudden appearance of life forms is called the "Cambrian explosion," and paleontologists now say the pattern of life looks more like a lawn than a tree. A recent article in Scientific American was titled "Uprooting the Tree of Life."
Another "icon" found in most textbooks is the Galapagos finches, which supposedly inspired Charles Darwin to frame his theory. Yet the finches actually refute his theory.
In the 1970s, after a drought hit the Galapagos Islands, researchers found that average beak size among the finches increased slightly (the thickness of a human thumbnail). Apparently, only larger birds could eat the tough, dry seeds that remained. This was hailed as a vivid demonstration of natural selection.
But in the early 1980s, heavy rains revived plant life on the islands, and the finch beaks returned to their original sizes. In other words, the change was merely a cyclical variation in an overall stable population. The finches provide no evidence that small changes can add up for long periods in a single direction, which is the heart of Darwin's theory.
Then there's Archaeopteryx, widely touted as the "missing link" between ancient reptiles and birds. Fossil evidence of true birds has been found earlier than Archaeopteryx, however, and consequently it has been demoted to an evolutionary dead-end.
Several other "dino-birds" have been proposed as the ancestor of modern birds, but none is widely accepted. Researchers are so desperate that some have actually presented reconstructions of dinosaurs with feathers painted on-even though the fossil itself had no feathers at all. This comes close to outright deception.
The public deserves to know what's true and what's little more than hype, especially when it comes to a theory as influential as Darwinian evolution-and especially when that theory is used to promote an ethic that treats human life as expendable. Many of the best-known "icons" of evolution are outdated and discredited. Yet they continue to live on in textbooks and museum exhibits-and in moral arguments that devalue human life.