Alaska's Supreme Court ruled the state discriminates against same-sex families by not allowing access to property tax exemptions reserved for senior citizens and disabled veterans.
The legal rights group American Civil Liberties Union announced the court's decision on 25 April.
The case was brought by three couples denied a $150,000 (€108,000) property tax exemption the western US state makes available to opposite-sex married couples.
Because a constitutional amendment bans gay marriage the state treated the plaintiffs as roommates. Their exemption was only equal to half the value of the couples' homes.
'For purposes of analyzing the effects of the exemption program, we hold that committed same-sex domestic partners who would enter into marriages recognized in Alaska if they could are similarly situated to those opposite-sex couples who, by marrying, have entered into domestic partnerships formally recognized in Alaska,' the Alaska Supreme Court wrote, as reported by Reuters.
The ACLU hailed the judgment.
'Our senior citizens and veterans should not have to pay more taxes just because they happen to be gay or lesbian,' Joshua Decker, executive director of the ACLU of Alaska, said in a statement.
The lead plaintiffs, Julie Schmidt, 71, and Gayle Schuh, 66, have been together 36 years. The former educators are originally from Illinois, a midwestern state.
'Gayle and I built a home and a life here because we loved what Alaska had to offer,' Schmidt said in a statement. 'It hurt that the state that we loved so much treated us like strangers. It is gratifying to have our relationship recognized.'