In his State of the Union Address last week President Bush portentously warned us about a creature waiting to burst forth from our biology labs: human-animal hybrids. Surely it would be pointless and disgusting to create such things, and no scientist is contemplating doing that, so what was the president talking about?
What President Bush was likely discussing were chimeras: individuals made up of genetically different types of cells. Some human beings are chimeras; the result of the merging of two embryos, they are one person with two blood types (no one knows why this sometimes happens). Some non-identical twins are also chimeras, because for a time they shared a blood supply and their cells mixed. Chimeras are invaluable in the fight against disease; scientists create lab animals that, for example, produce human proteins, so that drugs can be tested on them before they are tried on human patients.
There are dozens of types of such animals in labs all over the world. Stem cell research would indeed be applied to making new and better animal models of human disease. But these animals aren’t hybrids, they’re chimeras.
Now in fairness we can’t expect presidents to be experts in everything, but we can expect their speechwriters not to embarrass them with their own ignorance. President Bush was poorly served by his staffers, who apparently don’t know the difference between a hybrid and a chimera. All they had to do was Google the terms and they would have discovered that a hybrid is the offspring of two genetically different animals, like a mule, which is the sterile product of a male donkey and a female horse.
In their confused way, what President Bush and his writers seem to have been referring to were lab animals that, for example, could be made to have pancreatic cells with human genes, so that new drugs for diabetes could be tested on them rather than children. Is President Bush really against that?
Or perhaps the president and his wordsmiths are really worried about people with animal cells in them. In that case you’d better steer clear of Uncle Fred with his porcine heart valve. He’s a chimera!
But this isn’t a political game of “gotcha.” For millions of people it’s a matter of life and death. Bush’s confused reference to hybrids came in the same passage in which the president was reaffirming his opposition to human cloning – also something every reputable scientist, science advocate, and science organization in the world is on record opposing. Rather than working to advance real life-saving science, the president used his State of the Union Address to confusedly decry science-fiction procedures that no credible scientists are even considering pursuing.
We understand that presidents and their aides mix up scientific concepts now and then. The trouble starts when they then present themselves as the ultimate authorities on where science should go.
Stem Cell Fact Sheet (PDF), May 26, 2006
Jonathan D. Moreno, Ph.D., is Kornfeld Professor and Director of the Center for Biomedical Ethics at the University of Virginia and a Senior Fellow at the Center for American Progress.