RALEIGH, N.C. (AP) – A state lawmaker’s custody fight is one of several pending court cases that highlight the lack of clarity in North Carolina law over what makes a person a parent.

State Sen. Julia Boseman has filed a lawsuit seeking joint custody with her former partner of their 4-year-old son. Boseman, D-New Hanover, is the Legislature’s only openly gay member, but legal experts say the law is vague with regard to all unmarried couples.

“There are many millions of children in this country who are being raised by people of the same sex who are not married, people of the opposite sex who aren’t married, grandparents, stepparents and psychological parents,” said John Mayoue, an Atlanta family law attorney who writes on custody issues.

The ambiguity of North Carolina’s law is not uncommon among states, with courts and legislatures falling behind societal changes in family structure as well as medical options such as surrogate mothers and sperm or egg donors.

Sharon Thompson is a former legislator now in family law practice specializing in helping same-sex couples. Thompson said she has handled cases where donors didn’t intend to be legal parents but could only keep their names off a birth certificate by getting a court order determining who the child’s parents would be.

In another situation, officials refused to put both the genetic mother, who donated the egg, and the birth mother on one certificate.

“The state agency that issues birth certificates is sometimes at odds with a judge’s interpretation,” Thompson said. “It hasn’t been addressed on a statewide level.”

Boseman is seeking secondary custody of the boy conceived through artificial insemination and born in October 2002 to her partner, Melissa Jarrell, who would retain primary custody. The couple split up last year, and the boy has spent time with both women, the lawsuit said.

“We’re working through this matter as a family and we’ll resolve it as a family,” Boseman said, declining to discuss the case further. The action, filed in January, has not gone to trial.

A similar dispute in Durham is expected to be heard before the state Court of Appeals either late this year or early next year.

Irene Dwinnell is trying to overturn a trial court’s decision last year that gave her former partner, Joellen Mason, joint custody of a son whom Dwinnell conceived through artificial insemination by an unknown donor.

In court filings, Dwinnell argues that only her name is listed as a parent on the boy’s birth certificate. The difference in Boseman’s case is that Boseman legally adopted her son.

That can be difficult for same-sex couples to do in North Carolina, where the law neither explicitly prohibits nor allows such adoptions.

“Many lawyers are surprised and think you can’t do it. But there are judges who think it is possible to do this under current law,” Thompson said. “We’ve been doing it quietly.”

Some conservatives worry that courts might be too willing to grant custody rights to non-biological parents in same-sex relationships.

“It would raise concerns among the vast majority of people in North Carolina,” Sen. James Forrester, R-Gaston, said. “That’s an unhealthy relationship for a child to grow up in. The Lord intended for a family to have one man and one woman.”

But Thompson said courts should act based on what’s right for the child.

“It’s in the child’s best interests to continue to have a significant relationship with someone who has acted as a parent in their life,” she said. “These kids don’t know any difference, whether this person is a legal parent or not. They just know who tucked them in at night.”