APA, which represents more than 154.000 psychologists, voted unanimously to support same-sex marriage and requires a federal legislation.
"Now as the country has really begun to have experience with gay marriage, our position is much clearer and more straightforward — that marriage equity is the policy that the country should be moving toward," says Clinton Anderson, director of APA's Office on Lesbian, Gay, Bisexual and Transgender Concerns.
For them, the marriage is a significant component for people.
"Many gay men and lesbians, like their heterosexual counterparts, desire to form stable, long-lasting and committed intimate relationships and are successful in doing so,"explains the APA in its report.
"Emerging evidence suggests that statewide campaigns to deny same-sex couples legal access to civil marriage are a significant source of stress to the lesbian, gay and bisexual residents of those states and may have negative effects on their psychological well-being."