The Delaware Supreme Court issued a ruling March 14 upholding the right of a woman to be identified as a “de facto” parent of a child she had been raising with her former same-sex partner—a child the partner adopted but that the woman herself did not. The ruling was based on the amending of a state law to expand the state’s definition of a “parent” to give full, equal rights to lesbian and gay parents who may not have biological or adoptive ties to their children.

The custody battle between the women not only relied on the amended law, but, in an earlier phase, it had motivated the legislature to amend the law. And in its decision, the Delaware Supreme Court ruled against a challenge to the newly amended law’s constitutionality.

The state Supreme Court ruling upheld a lower court decision stating that Carol Guest had the right to joint custody of the child she had been raising with her former partner, Lynn Smith, even though Smith was the only one who had adopted the child. (The names in the case are pseudonyms used by the court.)

Smith and Guest had obtained the child through a service in Kazakhstan, but that country does not permit two women to adopt a child jointly. Because of that, only Smith filed papers to legally adopt the child in March 2003, but both women raised the child together. According to court documents, a lawyer advised the couple in June 2003 that Guest could petition for adoption in the United States after she lived with the child for a year, but Guest did not do so and the couple split in May 2004. Smith cut off Guest’s contact with their child shortly after that.

The case made two passes through the state courts.

When Guest initially sought custody and visitation through the Family Court, in 2004, Smith countered that Guest had no standing to bring a custody action under the Delaware Uniform Parentage Act (DUPA), which defines who may be considered a “parent” under state law. But the Family Court ruled for Guest in June 2006, saying she had standing as a “de facto” parent—someone who acted as a parent to the child—although she was not a legal parent.

The Supreme Court in February 2009 overturned the Family Court’s ruling and denied Guest custody. The court said the DUPA did not recognize de facto parents and noted that changing the law “is a public policy decision for the General Assembly to make.”

The legislature did so in July 2009, amending the DUPA to define a “de facto” parent as someone who has the “support and consent” of the legal parent(s) and has acted as a parent to that child for long enough to have established “a bonded and dependent” parental relationship with the child.

After Guest went back to the Family Court and was granted custody under the new law, Smith challenged the decision and appealed to the state Supreme Court, which considered the women’s situation for a second time.

This time, Smith claimed the Family Court ruling violated her right to raise her child, as maintained by the 2000 U.S. Supreme Court case of Troxel v. Granville. In that case, the high court struck down a Washington state law that allowed any third party—such as a grandparent—to petition for child visitation rights, even if the parents objected.

But the Delaware Supreme Court said that the cases differed because, in Troxel, the third party had no claim to a parent-child relationship.

“Guest is not ‘any third party,’” the court explained, but a “de facto” parent. As such, under the newly amended law, she is also a legal parent of the child and has “a co-equal ‘fundamental parental interest’” in raising the child.

The definition of “de facto” parent varies from state to state, and not all states give de facto parents full legal status, as does Delaware, explained LGBT family law expert Nancy Polikoff, in an interview. Some states may recognize them as having a claim only to visitation or custody, but not as full parents for the purpose of government benefits and inheritance rights.

Only four other states—Maine, New Jersey, Pennsylvania, and Washington—will, like Delaware, recognize non-biological, non-adoptive parents as having the full rights and responsibilities of parentage. They base their recognition on the person’s relationship with the child, according to the National Center for Lesbian Rights, in an October 2010 fact sheet, “Legal Recognition of LGBT Families.”

States that recognize marriage or civil unions of same-sex couples may also recognize non-biological, non-adoptive parents as full parents under state law. But in Delaware and the other four states, the parents’ rights are based upon their relationship to the child, not to the other adult. Their parental rights are thus not subject to challenge under the Defense of Marriage Act (DOMA) or other state laws banning the recognition of same-sex relationships.