It may be the litmus test for the 2012 election cycle. It’s certainly shaping up that way for a lot of Democrats.

Two-thirds of democrats and half the independents polled by the Pew Forum on Religion and Life last month support gay marriage.

And although only 24 percent of Republicans share this attitude today, even the GOP shows a steady growth in support over time.

Key to the change in attitude appears to be a change in how society views homosexuality in general.

For example, a 2011 research study of adolescents found that “beliefs that homosexuality is biological or genetic are related to lower levels of sexual prejudice.” These students were “more likely to judge exclusion and teasing based on sexual orientation as [morally] wrong.”

Similarly, students who believed that homosexuality was a lifestyle choice “were less tolerant and accepting of gay and lesbian people.”

From the Pew study:

A Los Angeles Times survey in 1985 found just 20% of the public believed that homosexuality was something that people are born with, while twice as many (42%) said it was just the way some people prefer to live. Today, the balance of opinion is quite different: 41% say homosexuality is something people are born with, while 35% say it is a personal preference.

[…]

Those who believe homosexuality is something people are born with have consistently been the most supportive of gay marriage, and that support has risen substantially in recent years, to 76% in the new poll. By comparison, there has been little change among those who say homosexuality is the way that some people prefer to live; 63% of this group opposes gay marriage.

Nature or nurture, that is the question.

In 2008, the world’s largest study of twins suggested that sexual orientation — homosexuality or heterosexuality — is “largely shaped by genetics and random environmental factors.” According to study co-author Dr. Qazi Rahman:

Overall, genetics accounted for around 35 per cent of the differences between men in homosexual behaviour and other individual-specific environmental factors (that is, not societal attitudes, family or parenting which are shared by twins) accounted for around 64 per cent. In other words, men become gay or straight because of different developmental pathways, not just one pathway.

Also in 2008, another set of researchers tested a hypothesis about why homosexuality persists across time and cultures.

They conclude that only one theory fits the data. The theory is called “sexually antagonistic selection” … The gene for male homosexuality persists because it promotes—and is passed down through—high rates of procreation among gay men’s mothers, sisters, and aunts.

Research reported this year in The Journal of Sexual Medicine echoed that finding: “Our analysis showed that both mothers and maternal aunts of homosexual men show increased fecundity compared with corresponding maternal female relatives of heterosexual men.”

Conversely — or not surprisingly, depending on your worldview — the Catholic Medical Association writes that the “cause” of homosexuality is “developmental-psychological, not genetic or physiological.” To “overcome” homosexuality requires “simultaneously addressing the emotional, moral, and spiritual components of the psyche.”

I’ve just flashed back to the 1950s and Alan Turing’s “treatment” for homosexuality.

I’d like to believe that we are past this, but it is symptomatic of the larger role of science in cultural beliefs.

Moreover, a Washington Post analysis of the presidential race suggests I’m dreaming.

The WaPo reports that 30 states have constitutional amendments banning same-sex marriage; 60% of American voters live in these states. Only one “solid blue” state (Minnesota) has such an amendment; most of them (21) are “solid red.”

What does this mean for Washington state in November? Which way will voters lean on Referendum 74; will we ratify or veto state legislative action on gay marriage?

The Pew poll was conducted by telephone June 28-July 9 among a random national sample of 2,973 adults (774 self-identified Republicans, 995 Democrats and 1,037 independents). Results among all adults have a margin of error of +/-2.1%; analysis of each sub-group has a larger margin of error.

:: Follow me on Twitter!
:: Circle me on G+