Child custody cases create passionate courtroom battles. In Michigan, a Monroe County Court judge is hearing a case that could give some clarity as to the legal parameters of parenthood in custody cases involving children born to same-sex parents before the Supreme Court legalized gay marriage.  In the courtroom is a lesbian former couple, Jessica Zunk and Carin Hopps, who built their family with the assistance of in vitro fertilization (IVF).

Their daughter is seven and their son is five years old.

Hopps, 47, is a medical doctor who used her own eggs and sperm from a donor to conceive their daughter. For the birth of their son, however, both an egg donor and sperm donor were used, though Hopps carried and delivered the baby.

Her former partner, Jennifer Zunk, 51, is a teacher who performed many of the family duties including childcare, driving the children to school, taking them to doctors’ appointments and much more.

According to court documents, Zunk was granted limited guardianship of the children in 2011. Hopps wants to terminate this since the couple is no longer in a relationship.

Oralander Brand-Williams, a reporter for the Detroit News, wrote that Zunk’s attorney, Dana Nessel, questioned the issue of the son’s parentage asking, “How is Carin any more a parent to the couple’s son than Jennifer is when the Michigan Child Custody Act requires a person to be a parent either though nature (biology) or adoption? Neither woman has a biological relationship to that child, nor has either woman adopted him.” She went on to say, “Hence, under the law as it currently stands, the boy has no parents. If the court terminates the guardianship of Jennifer today, the boy has no parent and, therefore, becomes a ward of the state.”

And that, quite frankly, is an excellent argument.

This case, especially in relation to the son, raises the important question of parentage for those in non-marital relationships who have no biological link to their children, particularly for couples co-parenting before the historic U.S. Supreme Court judgment made gay marriage legal in the United States last summer.

Both women were mothers to their children, with Zunk known to the children as “Teacher Mom” and Hopps known as “Doctor Mom.”

Brand-Williams reported, “The couple decided to end their relationship in October 2014 although they lived together until the following February.” She continued, “Hopps filed court papers to terminate Zunk’s guardianship of both of the children in January. A month later, Zunk filed a complaint seeking joint legal and physical custody of the children as well as parenting time and child support.”

The next hearing is on the docket for May. The judge will be listening to arguments from both sides and may quickly arrive at a decision.

As the reporter noted, legal experts are declaring this case incredibly important due to the fact that parentage issues for same sex couples and their children born prior to the legalization of gay marriage is unsettled.

Nessel describes the case as one that is treading in “uncharted territory.”

She told the judge at the last hearing, “How can you deny a finding of equitable parenthood to our client when, according to the U.S. Supreme Court, they were unconstitutionally denied the right to marry?”

Nessel was also quick to point out how this legal issue also transcends to heterosexual couples. There may be unmarried couples in committed relationships who have undergone third-party reproduction and whose co-parenting rights could be compromised because there is no “law on the books” addressing the parentage rights of individuals in this category.

Legal experts are hoping that the Michigan Legislature puts some teeth in their child custody laws to protect children conceived through third-party reproduction to unmarried parents. In this new family building era, where parentage can be defined beyond biology, the law needs to make strides to protect the rights of those who cannot rely on their marital status as a safeguard.