I WAS INTRIGUED to learn last week that one of the United Nation's leading candidates for Iraqi leadership is Dr. Hussain al-Shahristani, a nuclear chemist and former science adviser to Saddam Hussein. Al-Shahristani spent more than a decade in Abu Ghraib prison for refusing to participate in Hussein's weapons program and finally escaped during the Gulf War.

Despite President George W. Bush's virulently antiscience agenda at home, the president is touting al-Shahristani for the job because his status as a scientist makes him a religious and political nonpartisan. But this move also underscores the extent to which science is deeply bound up with a political agenda. Even ultra-groovy, science porn magazine Seed – which is usually about as political as an issue of Cosmopolitan – has a cover story this month on how readers can "vote science" in the coming election.

Of course, voting science, or even sticking to a science party line, isn't as easy as you might imagine. As Stanford University evolutionary biologist Joan Roughgarden points out in her new book, Evolution's Rainbow: Diversity, Gender, and Sexuality in Nature and People (UC Press), the factions that divide the scientific community are practically religious in their dogmatic adherence to particular interpretations of nature. Roughgarden's book is a challenge to more than a century's worth of scientific inquiry into "sexual selection," a term Charles Darwin used to describe the way mate choices contribute to the evolution of a species. She explains that there are two camps in the debate over evolution, each with its own political agendas: one argues that the survival of a species is secured solely through sexual selection, while Roughgarden and others argue that survival is more properly understood as a result of social cooperation.

Strict sexual selectionists hold that females guide the evolution of their species by choosing the "fittest" mates to father their children. Richard Dawkins enshrined this idea in his influential book The Selfish Gene, which postulates that genes compete (selfishly) for their own preservation, fighting with other genes for the opportunity to survive through the offspring of the species' choosy ladies. From this point of view, the only players in evolution are heterosexual reproducers.

Interpreted in this light, it would seem that nature is voting for the "rightness" of heterosexuality, relegating all other forms of sexuality to the ash can of the genome.

And yet, in species after species, we find nonreproducing and non-heterosexual creatures helping the group to survive. Female worker bees, for example, contribute to the survival of the hive without ever mating. Several species, including certain monkeys and dogs, form families with one mother and several fathers in order to rear their young. Whiptail lizards and hundreds of other species routinely engage in homosexual pair-bonding. If sexual selection and its selfish genes are the only story, Roughgarden asks, why do we find so much sexual diversity in nature?

She suggests we consider the possibility of a "genial gene" that selects for creatures who share the work of species survival without competing to pass their genes on. The endurance of homosexuality in animals suggests a social cooperation principle is at work, because homosexuals often contribute to the survival of the species without reproducing sexually. It's easy to see what the political agenda of a social cooperation model would be. This model suggests that nature votes yes on sexual diversity: our species requires more than baby-makers to survive – it needs caretakers, thinkers, protectors, laborers, and all kinds of other people to keep us from becoming extinct. Evolution depends on social cooperation, and heterosexual reproduction is just a small part of that. Nature votes yes on gay marriage!

Sometimes, however, the politics of science hinge on economic issues rather than social ones. As Eric Lerner and dozens of other physicists pointed out in a recent public statement (www.cosmologystatement.org), the future of cosmology is being threatened because there's no funding for people who want to research alternatives to the big bang theory of how our universe formed. Many physicists are now criticizing big bang theory because it requires them to invent all kinds of crazy, unproved shit like dark energy and dark matter in order to fit with their observations of the universe. But if all the funding agencies are controlled by big bang adherents, no one will ever be able to test the theory's validity by proposing alternative models for how the universe formed. As long as the big bang guys have all the money, you're missing out on your chance to learn more about the steady-state model of the universe and plasma cosmology.

Like religion, science isn't a unified set of principles: it's a bunch of politicized factions. So when you vote yes on science, be sure you know whom you're voting for.