Same-sex couples in Montana now have the same rights as married couples to pursue child custody in court.

The Montana Supreme Court, in a 6-1 ruling, upheld that right Tuesday. Justices decided a woman who shared responsibility for two adopted children with her former partner was entitled to parental rights.

Montana law does not allow same-sex couples to adopt children, so only one partner can legally be regarded as the adoptive parent. According to court documents, Barbara Maniaci and Michelle Kulstad agreed that Maniaci would be the adoptive parent on all the legal paperwork, but the two of them would raise the children together. As a result, Kulstad was not listed as the legal parent.

Some people hailed Tuesday's ruling as a victory for people -- gay and straight -- who care for children outside the bounds of traditional marriage. Others said it opens the doors to outside parties who want to lay claim to children.

"This is a victory for families in all shapes, sizes and colors," Betsy Griffing, the legal director of the Montana branch of the American Civil Liberties Union, told the Billings Gazette.

Broadening the definition of family is not necessarily a good thing, wrote Justice Jim Rice in the sole dissenting opinion. Anyone who has spent a lot of time caring for children can make legal claims for custody, he wrote in his decision.

"Now even parents who are fit and capable are potentially subject to claims of third parties for the rights of their children," he wrote. "Consequences of geometric proportion will fall in the future upon many fit parents."

Maniaci and Kulstad lived for 10 years together near Missoula, Mt. They exchanged rings and raised two adopted children (now ages 9 and 6).

After the couple separated in 2006, Kulstad sought joint custody rights with the children. Maniaci has since remarried to a man.

Justice Brian Morris wrote the majority opinion and said state law allows nonparents to seek a "parenting interest" if a parent-child bond has been established. "Maniaci cannot rewrite history of the fact that she and Kulstad lived together for more than 10 years and jointly raised the minor children in the same household," he wrote.

It can only be discrimination to shut out homosexuals from the law, he added.

"Naming it for the evil it is, discrimination on the basis of sexual orientation is bigotry," he wrote. "Lesbian and gay Montanans must not be forced to fight to marry, to raise their children and to live with the same dignity that is afforded heterosexuals."