The rise of non-traditional family arrangements and the legalization of same-sex marriage have put states in a quandary: How to look out for the welfare of a child when “mother” or “father” aren't necessarily tied to offspring by biology, adoption or marriage? Last week, the Maryland Court of Appeals set a new standard recognizing the right of “de facto” parents.

In Conover v. Conover, the state's highest court ruled unanimously that that an adult regarded as a de facto parent can have standing to contest custody or visitation decisions without necessarily demonstrating parental unfitness or exceptional circumstances. Instead, state courts must recognize the evolving nature of family relationships and should ultimately be guided by the best interests of the child, the judges ruled.

The case that inspired this new standard reflects many of the quandaries facing contemporary family court judges. Brittany and Michelle Conover began their relationship in 2002. In 2009, a son, Jaxon, was conceived through artificial insemination. The birth certificate listed Brittany as the mother but did not list a father although, as the record shows, Jaxon grew to call Michelle “Dada” or “Daddy.” They married in 2010 in the District of Columbia where same-sex marriage was legal.

In 2011, the couple separated. One year later, Brittany was denying visitation rights to Michelle. In 2013, they both filed for divorce. Michelle asked a Washington County judge for visitation rights but was ruled not to have standing because she could not prove herself a “father,” in part, because she was female. That position was upheld by the state Court of Special Appeals, which found it consistent with the view of same-sex couples reflected in a 2008 Court of Appeals decision in a similar same-sex custody case, Janice M. v. Margaret K., that rejected the concept of de facto parents.

With Thursday's ruling, the high court has essentially reversed that view, calling the Janice M. case “clearly wrong.” But figuring out exactly who should qualify as a de facto parent remains a question likely to be disputed — and perhaps to be taken up by the General Assembly when it reconvenes in January.

Since the issue of de facto parenting isn't addressed under existing statute, the court endorsed standards set forth under a Wisconsin Supreme Court decision: That the biological or adoptive parent consented to and fostered the third party's parent-like relationship, that they lived together in the same household, that the de facto parent took on significant responsibility for the child's care, education and development without expectation of financial reward, and the parental relationship lasted long enough for them to be bonded and the child to feel dependent.

No doubt some will be displeased to see the judges go so far as to set such specific criteria for a legal standard that lawmakers haven't themselves even debated (and on this point there was, indeed, dissent within the court). But it strikes us as an entirely appropriate, common-sense framework in an area of law that badly needs updating in the face of changing family dynamics and social customs. And it brings Maryland in line with a majority of states that have already recognized de facto parenting

Divorce and child custody decisions have always been a messy and difficult business with, as Judge Sally Adkins writes in the opinion, “grave implications for all parties.” The case isn't resolved by the Court of Appeals ruling, only the legal standing of Michelle Conover, who, according to a court filing, transitioned to living as a transgender man after the divorce. Now, the matter of visitation will be back in the hands of the lower court.

What constitutes a parent? Clearly, the answer to that question has evolved over time, and the law has failed to keep up with that social progress. The Maryland Court of Appeals has now taken an important step in filling a legal void. If the legislature can do better, they are welcome to try — assuming they will recognize the 14th Amendment equal-protection rights of all, including members of the LGBTQ community, while protecting the best interests of children. But until they do, the court's de facto parent framework that recognizes a greater breadth of family bonds is a marked improvement over the outdated status quo.