A lesbian who split with her partner after adopting the woman's biological children must pay child support, the Indiana Court of Appeals (search) has ruled.

The woman adopted her partner's children in 1997. A few years after their breakup, she tried to vacate the adoption. Around the same time, the children's biological mother, who had remarried and divorced a man, filed for child support.

A three-judge panel ruled Wednesday that the woman who adopted the children must contribute to the cost of raising them.

"Whether a parent is a man or a woman, homosexual or heterosexual, or adoptive or biological, in assuming that role, a person also assumes certain responsibilities, obligations, and duties," Judge John G. Baker (search) wrote in a 22-page ruling.

"That person may not simply choose to shed the parental mantle because it becomes inconvenient, seems ill-advised in retrospect, or becomes burdensome because of a deterioration in the relationship with the children's other parent," the decision said.

The ruling is part of a growing and sometimes contradictory body of family law grappling with gay and lesbian relationships.

The appeals court ruled in November that a person may adopt the children of a same-sex partner and retain parental rights, such as visitation privileges, following a breakup. Yet last month, the court found that state law defines marriage as a union between a man and a woman.

Ellen Andersen, a professor at Indiana University-Purdue University at Indianapolis who follows gay rights issues (search), said Friday that there is tension between the court's rulings.

"The law is progressing, and as happens a lot as laws are reacting to social movement changes, there's a lot of one-step forward, two-step backing," she said.