This Wash Times story says:
Fathers' rights groups cheered a state appeals court ruling for Manuel Navarro as a victory for "paternity fraud" victims, but their celebrations may be short-lived. The Los Angeles County child-support agency has asked for the appellate court ruling to be "depublished," or omitted from official records, so no other man can use it to overturn his child-support order. ...So the Los Angeles County child-support agency wants to continue fraudulently gouging non-fathers for child support, and hide the court decision that would get the innocent men off the hook! (In spite of the agency's request, the decision was published.)
Mr. Navarro said he was never properly served child-support papers and was assigned child support in absentia. He recently underwent a DNA test that proved he was not the father of the boys.
When he went to court with his proof, however, the trial court ruled that Mr. Navarro still had to pay the child support because he did not protest it in time.
Mr. Navarro appealed and, on June 30, the appellate court handed him a victory, reversing the trial court decision and declaring that Los Angeles County "should not enforce child-support judgments it knows to be unfounded."
There is currently a proposed California law (AB 252) that is intended to supercede the Navarro decision. The law would authorize a court to set aside a voluntary declaration of paternity under certain circumstances, unless it determines that denial of such action is in the best interest of the child.
Apparently there is case law that says that there is no way to take any action, criminal or civil, against the mom who deliverately lies about who the father is for the purpose of false collecting child support.