Congress's Hybrid Problem

No, you haven't accidentally picked up a copy of Oilman Today. The hybrid problem of which I write is a bump on the road toward the United States Senate's passage of a bill to expand federal funding for embryonic stem cell research. It's a classic case of cutting-edge science signifying very different things to different observers, complicated by confusion about what the symbol at the heart of the controversy really means.

Stem Cells on the Hill Redux

The House passed its version of a bill to expand federal funding last year, after which Senator Bill Frist (R-TN), the majority leader who is also a cardiac surgeon, surprised observers when he announced that he supported the measure. These unexpected developments excited supporters of embryonic stem cell research. At one time, momentum looked rather favorable for majority passage sometime this summer.

The politics of this issue give opponents of the research headaches. On the one hand, clear majorities of those polled by the Genetics and Public Policy Center last year favor expanding federal funding, currently limited to support for research with a limited number of "approved" stem cell lines.¹ With President's Bush's approval ratings hitting record lows, Republican candidates in some states where the stem cell issue has been especially heated don't need more to worry about. Democrats have said that stem cells might be the domestic wedge that can "nationalize" local races in their favor. One object of Democratic yearning is the seat held by Senator Jim Talent of Missouri, who looks vulnerable and has said he opposes embryo-destructive research. A Senate vote would make it official, if nothing else. So the Senate leadership has some reason to want to take the issue off the table for the fall elections by approving the expanded federal funding, even if they later run into a presidential veto; at least they could tell constituents they tried.

On the other hand, with the conservative base already potentially dispirited, Republican operatives don't want to hand them another reason to be annoyed and stay home in November by appearing to retreat from one of the battlegrounds in the culture wars. Better to focus on an issue that will keep conservative voters happy and perhaps take advantage of crossover appeal to conservative Democrats and independents. A good candidate for this role is a constitutional amendment to define marriage as between a man and a woman, which could well occupy whatever space there is for "values" issues in the coming months.

The Minotaurs Are Coming

Underlying much of the political and philosophical opposition to emerging biotechnology, including stem cell research, is of course popular anxiety about a slippery slope toward fundamental and unmanageable changes in the nature of the human person. Much of the work of the President's Council on Bioethics has given scholarly voice to this worry. A particular symbol of this concern is the chimera. A creature in Greek mythology, the chimera is a fire-breathing animal with a lion's head and front paws, a goat's middle, a dragon's rear, and a snake for a tail. Notably, the chimera was killed by Bellerophon on another chimera, the winged horse Pegasus.

In modern medicine, the term chimera has been adopted to describe any individual with cells from more than one source. Unfortunately, this description is rather vague, so that a chimera can be anything from an animal with cells from another individual in that or another species, an individual that is the product of fused embryos, or a cardiac patient with a valve from a pig. Biologists mainly think of their lab animal models with tissues from different sources as chimeras.

Chimeric laboratory animal models of human disease have become an increasingly important tool for basic biomedical research, even apart from the possibilities of creating them using human embryonic stem cells. Examples of chimeras now under study: sheep fetuses to which human (nonembryonic) stem cells have been added in an attempt to make organs that may be transplanted into humans without immune rejection; pigs with some human blood cells to help explain how the AIDS...