Gay sheep and human destiny.

Just up the road from Brokeback Mountain, closeted away in their own private Idaho, the gay sheep were getting it on.

Well, it wasn't exactly private. They were doing it in front of scientists at the U.S. Sheep Experiment Station near the Idaho-Montana-Wyoming border. The scientists arranged the trysts. It's called "sexual partner preference testing."

According to an article by researchers involved in the project, here's how it works. In a 15-by-10-foot "arena," a young ram is offered four choices: two ewes in heat and two rams. "The four stimulus animals are restrained in stanchions so that they can only be approached from the sides and rear." For 30 minutes, the unrestrained ram does as he pleases. The scientists count his "anogenital sniffs," "mounts," and "ejaculations."

A bare majority of rams turn out to be heterosexual. One in five swings both ways. About 15 percent are asexual, and 7 percent to 10 percent are gay.

Why so many gay rams? Is it too much socializing with ewes? Same-sex play with other lambs? Domestication? Nope. Those theories have been debunked. Gay rams don't act girly. They're just as gay in the wild. And a crucial part of their brains—the "sexually dimorphic nucleus"—looks more like a ewe's than like a straight ram's. Gay men have a similar brain resemblance to women. Charles Roselli, the project's lead scientist, says such research "strongly suggests that sexual preference is biologically determined in animals, and possibly in humans."

Roselli's interest is in the science. He figured the political upshot, if any, would be gay-friendly. After all, surveys show that if you think homosexuality is biologically determined, you're less likely to be anti-gay.

Roselli didn't just prove homosexuality in rams was natural. He tried to engineer it. In a 1999 grant application, he proposed "to determine [whether male-oriented] preference behavior can be artificially produced in genetic male sheep" by depriving male lamb fetuses of estrogen stimulation. Seven months ago, he reported that the experiment failed. The point wasn't to promote homosexuality. The point was to learn what causes it.

You'd expect conservatives to demand that the government stop funding this research. But science is tricky. If you figure out how to make sheep gay, you can probably figure out how to make them straight. And maybe you can do the same to people.

Roselli studies hormones, brains, and behavior. He works at Oregon Health and Science University, a medical institution. But his collaborator, Fred Stormshak, is an animal scientist affiliated with Oregon State University, which focuses more on agriculture and economics. Gay rams are "a costly problem for sheep producers because breeding rams are worth $300 to $500 each," Stormshak told OSU's agricultural newsletter a decade ago. "Outwardly, there is no way to tell whether a ram is male-oriented, so the producer runs the costly risk of buying an animal that will never produce any offspring."

Identifying gay rams wasn't enough. In 2000, Stormshak described an attempt to "alter" them. The idea was to "enhance their sexual behavior or performance" by making them act like straight rams. Three years later, Roselli told an OHSU committee that, among other things, "information gained about the hormonal, neural, genetic, and environmental determinants of sexual partner preferences should allow better selection of rams for breeding and as a consequence may be economically important to the sheep industry." OSU president Ed Ray says the research "may define biological tests that can be used to identify" gay or asexual rams, "thus eliminating their use for general breeding purposes."