TOPEKA, Kan. - A Kansas sperm donor's battle to avoid being declared the legal father of a same-sex couple's child has some similarities to the fight for gay marriage, the man's attorney argued in court filings.

The Kansas Department for Children and Families has sought to have William Marotta of Topeka declared the father of the child born to Jennifer Schreiner in 2009. The state wants Marotta to be responsible for thousands of dollars in public assistant the state provided, as well as future child support.

Marotta has said he contacted Schreiner and her then-partner after seeing an ad they placed on Craigslist seeking a sperm donor and signed a contract waiving his parental rights and responsibilities.

Kansas law requires a physician to be involved in the artificial insemination process, but that didn't happen in Marotta's case, The Topeka Capital-Journal ( ) reported. In June, a Shawnee County district court judge said that meant he isn't entitled to the same protections given to other sperm donors.

Charles Baylor, who represents Marotta, argued in a filing earlier this month that state statute shouldn't discriminate against the lesbian couple by forcing the child to have a male parent.

"In October 2012, when this case was filed, it may have been legally justifiable to look only for a non-custodial male upon whom to pin an obligation of child support. That day has passed," Baylor writes in the filing.

The attorney noted that earlier this month DCF Secretary Phyllis Gilmore told reporters the agency doesn't prevent same-sex couples from serving in any way.

"It's showing that DCF is not discriminating against same-sex couples in the context of their being foster parents. So I don't know why DCF should discriminate against same-sex couples who have always been the parents to the child in this case," Baylor said.

Agency spokeswoman Theresa Freed said the department doesn't comment on pending litigation, though the state might issue its own court filing in the coming week.

"There are laws, policies and procedures put in place within the child support system that serve to protect the integrity of the system, ensuring that children receive the support to which they are entitled," Freed said.

The Kansas Parentage Act requires enlisting the help of a licensed physician during the artificial insemination process. That requirement went into effect in 1973.