Representatives of the top psychiatric group in the United States have approved a statement urging legal recognition of gay marriage.
San Francisco was the first US city to permit gay marriage
The American Psychiatric Association could become the first major medical group in the US to take such a stand.
Delegates at a meeting in Atlanta cited the "positive influence of a stable, adult partnership on the health of all family members".
A resolution could be approved by the organisation in July.
State arguments rage
The move comes as the Texas senate approved plans to ban gay marriage in the state constitution.
The issue will be put to voters later this year. Texas could then join 18 other states in banning same-sex marriage in their constitutions.
Oregon's Supreme Court recently nullified nearly 3,000 gay marriage licences issued last year.
President George W Bush voiced support last year for a US constitutional amendment, but has said little about it since his re-election in November.
Last month, Connecticut became the second state in the US to allow same-sex civil unions last month- and the first to do so without orders from a court.
Increasing numbers of people in the US believe marriage for homosexual partners should be considered legitimate, according to a recent poll by Gallup, reported by CNN and USA Today.
Some 39% of respondents believe same-sex marriage should be legal.
In 2004, marriage certificates were issued to same-sex couples by local governments in the states of California, Oregon, New Mexico and New York.
Last May, the state of Massachusetts allowed gay and lesbian partners to apply for marriage licenses, the first state-sanctioned homosexual weddings in the US.
Vermont is the only other US state to allow same-sex civil unions.