The number of same-sex households in California grew like it was on steroids in the past decade—six times faster than that of straight married couples, according to Bloomberg News.

“The population of homosexuals living together as partners climbed 36.2 percent, and the increase for married heterosexuals was 5.7 percent, according to census data released today,” [the story says. Several factors are cited for the increase, including more legal protections for gay and lesbian couples and the overturning of Proposition 8 which banned gay marriage (the ballot measure was ruled unconstitutional in August 2010, though a hold is in place until the appeals process takes place).

Meanwhile, heterosexual couples are delaying marriage (in fact, for the first time in the U.S. married households are a minority, while co-habitating opposite-sex couples increased).

The most compelling, indeed, the most promising notion offered for the increased number of same-sex headed households—is that increased social openness has made more same-sex couples feel comfortable identifying as such. Increased visibility, both politically and culturally, has changed perceptions and comfort levels—and not just in California. Other states cited as having big jumps in same-sex households were Alabama, Wyoming and Kansas.

The takeaway quote of the Bloomberg piece was from Gary Gates of the Williams Institute on Sexual Orientation Law and Public Policy in LA who put this social sea change in an eloquent nutshell: “The closet is getting smaller.”