( CNN ) -- The American Psychological Association is calling on state and federal officials to stop anti-gay legal measures and to legalize same-sex marriage . The scientific and professional organization 's guiding body voted unanimously at its annual meeting this week in Washington to declare its support for `` full marriage equality for same-sex couples . '' The resolution `` clarifies the Association 's support for same-sex marriage '' in light of new research , the group said . A similar resolution in 2004 opposed discrimination against same-sex relationships , but refrained from a more formal policy recommendation . Dr. Clinton Anderson , APA associate executive director , said that the timing of the resolution is an indirect result of several states ' legalization of marriage . `` We knew that marriage benefits heterosexual people in very significant ways , but we did n't know if that would be true for same-sex couples , '' said Anderson , who is also director of the APA 's Office on Lesbian , Gay , Bisexual and Transgender Concerns . Now that six U.S. states permit same-sex marriage , researchers have been able to conduct studies with those couples . The research , Anderson said , indicates that marriage `` does confer the same sense of security , support , and validation '' to same-sex couples as to heterosexual ones . The resolution also points to evidence that ongoing political debate about marriage creates stress for gay men and lesbians and perpetuates stigmas and prejudice about their communities . This stress can make people physically and psychologically sick , the APA says , calling the link between stress and illness `` well established . '' Maggie Gallagher , chairman of the board of the National Organization for Marriage , takes issue with the assertion that legalizing same-sex marriage would improve community acceptance of homosexuality . `` There is no evidence that gay teens are better off in Massachusetts , a state that has gay marriage , than they are in Wisconsin , a state which has passed a marriage amendment defining marriage as one man and one woman , '' she said in an e-mail response to CNN . Gallagher continued , `` The release of this statement is unfortunately going to undermine confidence in APA statements generally , I would predict . '' Both the National Organization for Marriage and the APA are skeptical of one solution to the gay-marriage debate : civil unions . Rhode Island NOM executive director Chris Plante is quoted in a press release on the NOM website calling the move `` nothing more than a Trojan Horse that will usher in same-sex marriage sooner rather than later . '' Elsewhere on its website , NOM calls for dealing with legal and economic benefits separately from any discussion of marriage or unions . The APA also feels that civil unions miss the mark . `` Anything other than marriage is , in essence , a stigmatization of same-sex couples . Stigma does have negative impacts on people , '' Anderson said . `` That 's the analysis that we 've come to and why we 've decided to support full marriage equality -- because domestic partnership or civil union will still convey the message that same-sex couples are not as good . ''
American Psychological Association : support for ` ` full disclosure " '' APA : Studies show same - sex couples have ` ` sense of acceptance , trust and validation '' Traditional marriage advocacy group 's chair says there 's ` ` no evidence '' for findings .