The case of a Kansas sperm donor being sued by the state for child support underscores the confusing patchwork of laws that govern how assisted reproduction is regulated in the United States.

Many states haven’t updated their laws to address the evolution of family structures, such as parenting by same-sex couples. Experts say as case law changes, families put themselves at risk by failing to seek legal advice.

In late 2012, Kansas officials went after a Topeka man who answered a Craigslist ad from a lesbian couple seeking a sperm donor. William Marotta thought he’d signed away his parental rights, but was deemed financially responsible when the women split and one sought public assistance.

The trio didn’t go through a doctor — the only way Kansas recognizes men as donors.