The California Court of Appeal has ruled that one little girl has two legal fathers and a mother, and the three of them are going to have to parent her together.

The decision takes on the traditional common law presumption that, when a child is born to a married woman, the husband is the legal father. The court marries that concept with California law, which allows for some situations where a child can have three legal parents. And this is one, the justices ruled.

The child, now 6, was born in 2012 to a married woman who had an affair with a co-worker, according to an opinion released Tuesday and signed by Third District Justice Elena Duarte, with Justices Harry Hull Jr. and William Murray Jr. concurring. None of the parents are named, nor is the child. The parents are identified by initials in the record.

The mother at first kept the father's real identity from her employer and her husband, according to Duarte. That's why the father—the mother's co-worker—didn't ask for paternity leave. The mother had told him she and her husband were separated, but they weren't.

Still, by the time the baby came, both men knew about the other, and they shared responsibility and love for the child, Duarte said. The biological father took the baby home with him about every other weekend, and she bonded with his mother, sister and nieces. He also paid child support. He thought the baby had his name until he learned otherwise from a chance glance at a prescription bottle when she was 8 or 9 months old.

The legal dispute didn't start until the child was 3 years old. That's when the biological father filed to assert his paternity. The mother and her husband objected, arguing many things, including that the move would jeopardize their marriage and put their other children at risk and interfere with their ability to make medical and other decisions. And they stopped allowing him to see his daughter, Duarte said.

Placer County Superior Court Judge Suzanne Gazzaniga ruled in favor of the biological father—after some missteps at first which she said were caused by misinformation from the mother. She also ordered mediation for future parenting disputes and to add the biological father's name to the child's—although not as the last name. With Tuesday's decision, the Court of Appeal upheld Gazzaniga.

“The trial court found that wife misled the court at an interim custody hearing, prolonging what the court later viewed as an unwarranted separation. Despite this period of separation, the court found the child was still bonded to all three parents and found this to be a 'rare' case where, pursuant to statutory authority, each of three parents should be legally recognized as such, to prevent detriment to their child,” Duarte said. “We shall affirm.”

Matthew Purcell of Forester Purcell Stowell in Folsom represented the biological father. He could not be reached immediately.

Stephanie Finelli, a Sacramento solo, represented the mother and husband. Finelli said she plans to ask the California Supreme Court to review the decision.

“I think it's an unreasonable outcome,” Finelli said. “I think it's a misapplication of the statute.” She said the California law allowing for three parents to share custody was “not intended to introduce a boyfriends — or potentially a girlfriend” into parenting decisions of a married couple. “It's unworkable.”

Duarte dispensed with the objections the mother and her husband put forth, including casting  the biological father was a “homewrecker.” Duarte said he had taken the steps the law would require to establish paternity—such as paying child support, bonding with the child, sharing in the care, letting it be known that she was his and allowing her to know his family.

To the married couple, Duarte  basically said: Deal with it.

“The adult parties to a marriage will either work out any marital challenges they face, or they will not. But generally, even if a marriage fails, the parties thereto will remain lawful parents of any child therefrom,” Duarte said.

The child, Duarte said, “is fortunate, to have two devoted fathers that care deeply for her, love her and are prepared to continue to play an active role in her life.”

Lucky girl.