TOPEKA, Kan. – A Kansas man who donated sperm to a lesbian couple after answering an online ad is fighting the state’s efforts to suddenly force him to pay child support for the now 3-year-old girl, arguing that he and the women signed an agreement waiving all of his parental rights.

The case hinges on the fact that no doctors were used for the artificial insemination. The state argues that because William Marotta didn’t work through a clinic or doctor, as required by state law, he can be held responsible for about $6,000 that the child’s biological mother got through public assistance – and future child support.

Angela de Rocha, spokeswoman for the Kansas Department for Children and Families, said that when a single mother seeks benefits for a child, it’s routine for the department to try to determine the child’s paternity and require the father to make support payments.

Marotta, a 46-year-old Topeka resident, answered an online ad in 2009 from a local couple, Angela Bauer and Jennifer Schreiner, who said they were seeking a sperm donor. The three signed an agreement relieving Marotta of any financial or paternal responsibility.

But instead of working with a doctor, Marotta agreed to drop off a container with his sperm at the couple’s home and the women successfully handled the artificial insemination.