LOS ANGELES — A ruling in actor Jason Patric’s custody battle could have repercussions for an unexpected population – women who use fertility treatments.

Legal experts say an appellate court ruling issued Wednesday in favor of Patric’s fight to regain visitation with his son could lead to changes in cases like his, in which a man donates sperm to a woman he knows and then maintains a relationship with the child.

The court decision doesn’t completely resolve Patric’s fight to reunite with Gus, the 4-year-old boy he fathered through in vitro fertilization with Danielle Schreiber, an ex-girlfriend who no longer wants the actor in their lives. The “Lost Boys” actor must still prove to a Los Angeles judge that he qualifies as a father through his actions.

But experts say the Patric case will have a lasting impact on certain paternity cases.

In California, sperm donors outside of marriage are assumed to have no parental rights or child support obligations. Problems arise when a man donates sperm to a woman he knows and then, as in Patric’s case, begins to establish a paternal relationship with the child.

In Patric’s case, a family law judge determined his role as a sperm donor who wasn’t listed on his son’s birth certificate precluded him from having an ongoing parenting role. But the appellate justices unanimously ruled that decision was flawed.

Melissa Murray, a Berkeley Law professor, said the ruling should prompt women receiving sperm donations from men they know to think twice about whether they maintain a relationship with the man. Doing so could lead to him being designated later by a court to be a parent.

Women who are married or receiving anonymous sperm donations would not be affected by the ruling.

Patric signed documents saying he intended to be a father to Gus and later signed school forms and other paperwork that parents traditionally sign.

— From news service reports