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Friday, Jun. 19, 2009

By John Cloud

We have known for at least a decade that hundreds of animal species — including birds, reptiles, mollusks and, of course, humans — engage in same-gender sexual acts. But no one is quite sure why. After all, same-sex couplings don’t usually result in offspring. (I say usually because when male marine snails pair with other males, one partner conveniently changes sex, allowing for reproduction.) Evolutionarily speaking, homosexuality should have disappeared long ago.

A yearlong study just completed at the University of California at Riverside offers several fascinating competing theories about why same-gender sexual behavior has endured. And although it’s gay-pride month — and the 40th anniversary of the Stonewall riots that sparked the gay-rights movement — not all the theories will give same-gender-loving humans a reason to celebrate. (See the top 10 animal stories of 2007.)

One particularly charged finding is that in most species besides humans, same-gender pairings rarely lead to lifelong relationships. In other words, when one attractive bonobo male eyes another in a lovely patch of Congo swamp forest, they occasionally kiss and then move on to other oral pleasures, but they don’t bother anyone afterward about trying to legalize their right to an open-banana-bar ceremony. In fact, they are likely to move on to girl bonobos: most animals that engage in same-gender sex acts do so only when an opposite-sex partner is unavailable.

And yet the study’s authors, Nathan Bailey and Marlene Zuk of UC Riverside’s biology department, report some exceptions, like the laysan albatross. Last year, researchers studying a Hawaiian colony of albatrosses found that nearly a third of all the couples involved two females who courted and then shared parenting responsibilities. (Albatrosses don’t have U-Hauls, so no lesbian jokes, please.) Male chinstrap penguins also form long-term relationships, at least in captivity. And some male bighorn sheep will mount females only after the females adopt male-like behaviors. (Watch a gay marriage wedding video.)

What explains all these variances? Here are some hypotheses I collected from Bailey and Zuk’s paper as well as from some of their original sources:

1. The boys-in-the-locker-room theory. Any guy who played sports in high school knows that homoerotic jokes and towel-snapping are an underlying part of the subculture. Similarly, male bottlenose dolphins use same-sex sexual behavior to maintain and strengthen their social relationships — although dolphins are far more explicit about their homosexual play, regularly mounting one another and (hide the kids’ ears here) sticking their noses into certain boy-dolphin parts. (Very regularly: roughly half of male dolphin sex occurs with other males.) Among bonobos, same-sex sexual behavior is also thought to ease social tension and facilitate reconciliation. And among garter snakes, male-on-male contact may allow some solitary males to thermoregulate and, therefore, survive.

2. The emasculation theory. Some male animals might mount other males as a way of denying them access to the ladies. For instance, as the Journal of Natural History noted in 2006, male dung flies often must compete violently to impregnate females. In those situations, "the most sensible strategy for beating a competitor in the race to an arriving female would be to mount him and remain in situ for as long as possible." Then, when the lady dung fly finally sails by, the aggressor male can pull himself out from the dominated male and — because he is on top — get above to the female faster.

3. The "oops" theory. Among insects, same-sex sexual behavior is usually a case of mistaken identity. Male fruit flies, for instance, may romance other males because they lack a gene that enables them to distinguish between sexes. Even more surprising, male toads can’t tell the difference between girl toads and boy toads, so males will routinely embrace other males, although the subordinate ones are equipped with a call that quickly results in the dominant male releasing. In other species, the "straight" males get tricked by other wily straight males who dress in animal drag: male goodeid fish, for instance, sometimes have a black spot that resembles a spot that females get when pregnant. Dominant males then court them rather than fight with them. While the dominant guys are busy courting the subordinate, ladylike fish, the latter are able to "sneak copulations with females," as Bailey and Zuk write. I’m going to dub this the Hugh Grant Theory: it’s not always the most masculine guy who gets the most girls.

4. The let’s-see-how-this-thing-works theory. Younger animals (particularly males, and including humans) sometimes engage in same-sex sexual behavior as practice, which may improve their reproductive success when they are ready for a heterosexual relationship later. Fruit flies who experiment with other members of the same sex as youngsters may have more baby fruit flies later on than those who don’t experiment.

5. The two-plus-one theory. Among flour beetles, males routinely force themselves on other males. According to Bailey and Zuk, there’s some evidence that sperm deposited during this male beetle rape is sometimes transferred to a female later on, increasing the chances that she will have offspring.

What all these theories have in common is that same-sex sexual activity is either an accident or a quirky genetic method of helping males impregnate females. Which raises the evolutionary question of why men and women who are exclusive gay and lesbian exist. One answer is that exclusive gays and lesbians are a relatively new creation: the concept of exclusive homosexuality barely existed before modernity; even a century ago, most same-sex-attracted men and women got married and had kids. (Read "Do Monkeys Pay for Sex?")

As Bailey, Zuk and many others have pointed out, no one has offered an adequate evolutionary explanation for the relatively recent development of exclusive homosexuality among humans. In January, the journal Evolution and Human Behavior published a paper exploring the idea that certain alleles increase the likelihood of homosexuality by blocking the effect of androgens during fetal development. Having all those alleles hampers the masculinization of some parts of the brain that affect personality, making you gay, the theory goes. Brothers of gay men who have only some of the alleles would turn out straight but less aggressive than typical guys. And because those brothers exhibit less psychopathology, they would attract more women and therefore have more kids. It was a provocative theory, but it turned out not to be proved: gay men’s brothers don’t actually have more kids than straight men’s brothers do.

So we’re stuck at square one. As the 40th anniversary of Stonewall approaches, the question that Alan Miller and Satoshi Kanazawa ask in their 2007 book about evolutionary psychology, Why Beautiful People Have More Daughters, has never been more relevant: Will "the liberation of homosexuals, which allows them to come out of the closet and not pretend to be straight" actually turn out to "contribute to the end of homosexuality?" We may not know for a thousand years, but it’s a great question.

 

Same-Sex overtures across species:

 

 

 

 

Bottlenose Dolphins
Possibly the most bisexual animal on earth, bottlenose dolphins engage in frequent same-sex sexual activity. Roughly 50% of male dolphin sex occurs with other males; the sex helps strengthen alliances among small groups.

 

 

 

 

Laysan Albatross
Nearly one-third of relationships observed in one Hawaiian albatross colony involved long-term female-female pair bonds. The females courted and then raised offspring together.

 

 

 

 

Fruit Flies
Male fruit flies that engage in same-sex activity may lack a gene that allows them to distinguish between the sexes, although forced social pairings in the lab can also lead them to same-sex behavior.

 

 

 

Dung flies
Some males may mount other males as a way to keep them down, quite literally — to keep them from accessing available females that are flying overhead. The dominant male dung flies then use the opportunity to get to the females first.

 

 

 

 

Bison
Male bison who mount other males do so to establish or reinforce dominance hierarchies in herds.

 

 

 

 

 

Flour Beetles
Males often forcibly mount other males. Some evidence suggests that sperm from both male flour beetles may be transferred to females during later heterosexual copulations.

 

 

 

 

Humans
Roughly 3% of our species is exclusively gay or lesbian, although another 5% to 10% is intermittently or permanently bisexual. Studies suggest that men are more likely to be gay the more older brothers they have.

Gay Rights,from Stonewall to Prop 8:

 

 

 

 

 

 

 

 

The Unlikely Rebellion
The Stonewall Inn was a seedy, mob-owned bar on Christopher Street in New York City’s Greenwich Village, a place where gay men and lesbians could drink and dance among themselves at a time when the city was cracking down hard on gay bars and homosexual life. There had been little protest against the harassment, but a bust at the Stonewall in the early hours of June 28, 1969 — and reports that customers were being beaten by cops — provoked a sympathetic crowd into two days of rioting. A revolution was born.

The Legacy of Stonewall
A month after Stonewall, the first gay-pride march was held. The riots had galvanized an outsider culture into out-in-the-open activism. There had been previous attempts to persuade heterosexual society to assimilate gays and lesbians (notably by the Mattachine Society, founded in 1951). But those were almost cordial affairs. Stonewall began a series of uprisings and mass action, often fueled by martyrdom, that would become a pattern for American gay politics in the decades ahead. As one provocative mantra put it: "We’re here. We’re queer. Get used to it."

 

The Counter-Revolution
The rise of gay politics and activism, however, was met by a massive counterreaction. The embodiment of that opposition in the 1970s was pop singer and ex–beauty queen Anita Bryant, a runner-up in the 1959 Miss America pageant. In 1977 she was instrumental in repealing a Miami–Dade County ordinance that prohibited discrimination based on sexual orientation. Leading a group called Save Our Children, she declared, "What these people really want, hidden behind obscure legal phrases, is the legal right to propose to our children that theirs is an acceptable alternate way of life." She promised to "lead such a crusade to stop it as this country has not seen before."

 

The Rise of Harvey Milk
Harvey Milk was not the first openly gay person to be elected to office in the U.S. (That was Elaine Noble, who was elected to the Massachusetts house of representatives in 1974.) But his election to the San Francisco board of supervisors in 1977 proved that the gay community could be organized into an electoral constituency. Milk’s political acumen and provocative style made him a hero. But it also earned him enmity — and made him the gay-liberation movement’s first great martyr.

 

 

 

 

 

 

Anger in the Streets
The seven-year sentence for ex-cop Dan White, the fellow supervisor who shot and killed both Milk and San Francisco Mayor George Moscone on Nov. 27, 1978, infuriated the city’s gay community. A jury acquitted White of first-degree murder, buying the defense’s argument of "diminished capacity" — what has gone down in history as the "Twinkie defense." The day the news broke, May 21, 1979, saw the start of the city’s White Night riots, as thousands of San Franciscans marched through the Castro district to City Hall, disrupting traffic and setting fires.

 

 

 

 

 

 

 

 

The AIDS Cataclysm
Whatever advances were made toward greater acceptance of gays was swept away by the hysteria surrounding AIDS. The disease was first reported in the U.S. in 1981 and very quickly was shorthanded as a gay plague, stigmatizing a community already in mourning. The ostracism and lack of both scientific and government responses to AIDS led the playwright Larry Kramer, above, to found ACT-UP, a group whose guerrilla protests and disruptive tactics helped dramatize the plight of all AIDS patients and in no small part provided the impetus toward the creation of drugs that have apparently turned the disease in the U.S. into a chronic illness rather than an automatic death sentence.

 

 

 

 

 

Revival and Resistance
A generation was lost to AIDS, but the tragedies did help rebuild sympathy for gays and lesbians. The very public coming-out of comedian Ellen DeGeneres in 1997 was the epitome of the trend. However, the 1990s also saw large roadblocks and severe defeats inflicted by powerful forces. The community’s political support set the stage for President Bill Clinton to make good on a campaign promise to allow gays to serve openly in the armed forces. But heated opposition watered it down to a cowardly "Don’t ask, don’t tell" policy. In 1996, Congress passed the Defense of Marriage Act, which prohibited the Federal Government from recognizing same-sex marriages.

 

A New Martyr
The October 1998 lynching of Matthew Shepard in Laramie, Wyo., gave the gay community a new rallying point — and an icon on which to attach the community’s sense of siege and hopes for change. His death inspired demonstrations across the U.S. His story became the subject of an influential and widely performed play, The Laramie Project, and his name is popularly attached to a bill that seeks to expand the 1969 hate-crimes law to include crimes motivated by the victim’s gender, disability, sexual orientation or gender identity. The House passed the bill in April 2009; Ted Kennedy introduced it into the Senate with 39 co-sponsors.

The Battle for Marriage
The pitched battle for American gays in the 21st century was for marriage equality. Massachusetts led the U.S. in recognizing same-sex marriages, in 2004. California followed in 2008, after a lawsuit brought on in part by the decision of Mayor Gavin Newsom to wed same-sex partners in San Francisco’s City Hall, an act that challenged the state’s referendum-based definition of marriage as being between a man and a woman. The California Supreme Court declared that law unconstitutional and allowed same-sex marriages to take place. That sent opponents on a crusade to undo the decision.

 

Embracing Gay Culture
As Massachusetts and California set the social and political debate, popular culture too began to reflect more gay themes. The movie Brokeback Mountain, starring Jake Gyllenhaal and Heath Ledger as illicit and tortured lovers in the American West, won director Ang Lee an Oscar and was nominated for Best Picture at the Academy Awards in 2005. That same year, Felicity Huffman was up for best actress for her transsexual role in Transamerica. TV had increasingly visible gay roles: the sitcom Will and Grace, about a gay man and his straight woman best friend, ran for eight years on NBC.

Pushing Back the Tide
Meanwhile, opponents of gay marriage rallied against what seemed to be a popular tide in its favor. In November 2008, they won enough electoral support in California to roll back the state supreme court decision with Proposition 8. Vociferous protests broke out, with demonstrators targeting perceived supporters of Prop 8, including African-American Christians, the Catholic Church and Mormons. Prop 8 was then challenged in court. But other states then began to recognize the legality of same-sex marriage: Iowa, Vermont, Maine and New Hampshire. In May, the New York legislature began debate on a law recognizing same-sex marriage.

 

California’s Solomonic Decision
On May 26, the same California supreme court that had declared a ban on same-sex marriages to be unconstitutional decided to uphold Prop 8, the voter initiative that successfully sought to reinstate the ban. The judges, however, declared that the 18,000 same-sex marriages that took place before the referendum passed would remain legal and valid. New battles loomed as gay activists coordinated legal maneuvers and perhaps even a new voter initiative in the Golden State.

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