IOWA CITY, Iowa (AP) — A mother who falsely represents the identity of the father of her child can be sued for fraud and ordered to pay back financial support she received, the Iowa Supreme Court ruled Friday.

The court reluctantly opened the door to claims of paternity fraud, a controversial and particularly messy area of litigation that had not been recognized in Iowa. Chief Justice Mark Cady warned litigants to use caution in bringing such cases, saying they would be hard to prove, emotional and embarrassing.

"In the end, it becomes painfully obvious that parties pushed into the justice system over a paternity fraud claim could never leave it unscathed, and the standards of justice will certainly be stretched to their limits, even if justice is attainable," Cady wrote in a concurrence to the 7-0 decision. "This consequence may cause many reasonable, caring people to simply leave the claim dormant for the betterment of others."

The court ruled that Joseph Dier of Grundy Center can sue Cassandra Jo Peters for fraud to try to recover money he spent supporting a daughter born in February 2009 who turned out not to be his. Dier, 28, claims Peters enticed him into believing he was the father to get money and that he supported them for more than two years.

In December 2009, Dier filed a court petition seeking full custody. Last year, Peters claimed Dier was not the father and requested a paternity test after she feared she would lose custody of the child, Dier alleges. Two subsequent paternity tests excluded him as the child's father.

Dier filed a lawsuit last year seeking to recover money he spent supporting Peters, 25, and the child, as well as legal fees he spent on the custody dispute.

Judge David Staudt threw out the case in September, ruling that the "current status of the law demands that this case be dismissed."

Friday's ruling overturns Staudt's decision, sending the case back for a trial. To prevail, Dier would have to prove Peters knowingly lied when she told him he was the father and that he was justified in relying on her claim. Dier can recover only the out-of-pocket expenses he spent supporting them and not legal fees, the court ruled.

Peters' attorney, Lynn Wiese, said Peters and Dier assumed Dier was the father and his client did not commit fraud. He had urged justices to bar lawsuits between misidentified fathers and mothers. He argued instead they should sue the biological fathers, who had gotten off without paying support.

"This sort of case won't come without a price," Wiese said, warning that young children could be forced to testify. "These will not be pleasant lawsuits."

Dier's attorney did not immediately return a call seeking comment Friday.

Justices said courts in other state have split on whether to allow paternity fraud claims. The Iowa Supreme Court had deadlocked 3-3 in 2004 on the issue, a split that upheld a lower court's decision barring such claims on policy grounds.

Courts in states such as Nebraska have barred the lawsuits by arguing they are too harmful for children and families. Judges in other states, such as Illinois, have found that allowing fraud victims to recover money outweighs the potential harm.

The Iowa justices sided with the latter camp Friday, ruling that paternity fraud claims "fit comfortably within the traditional boundaries of fraud law." Allowing such cases could also deter lying by mothers, they found.

"It is true that Dier's success in the litigation could diminish the resources that Peters has available in the future to support (the daughter), but this would be true of any lawsuit against Peters," Justice Edward Mansfield wrote. "We have never afforded parents a general defense from tort liability on the ground they need all their money to raise their children."

Iowa law says a man cannot recover past child support he paid once establishing he is not a child's biological father but is relieved from pending and future obligations. Mansfield said that law applies only to court-ordered child support and not voluntary payments, such as the ones made by Dier.

Cady said paternity fraud cases would be extremely difficult, not unlike divorce and custody disputes.

"The proceedings that ultimately unfold in a courtroom are not easy or pleasant for anyone involved," he wrote, "but the court is nevertheless necessary to provide a forum for addressing an alleged wrong that has already occurred within a family unit."