LOS ANGELES — When does a man become a father — the legally recognized parent of a child, responsible for support and eligible for custody? Historically, parenthood has involved something more than simply a biological connection. In some eras, that meant the law recognized only fathers who married the mothers. Today, recognition extends to unmarried parents who raise a child together.

The new question is whether it extends to a man who donates sperm to a woman and establishes a relationship with the child. Does he become a father if the child calls him “Daddy”?

This is the issue addressed by SB 115, scheduled for a hearing in the California Assembly this week. The bill is inspired by actor Jason Patric’s efforts to obtain custody of Gus, the son born to a former girlfriend through assisted reproduction. State law says a man is not a parent if he donates sperm to a woman other than his wife with the help of a doctor. At the time the law was passed, in-vitro fertilization did not exist.

If it becomes law, the bill will allow a sperm donor to establish paternity if he “receives the child into his home and openly holds out the child as his natural child.” It recognizes that, today, unmarried couples may conceive children with no clear agreement about the rights or responsibilities that will follow after the child is born.

That appears to be what happened with Patric and Danielle Schreiber, who tried to have children without commitment to a continuing relationship. Schreiber had had a miscarriage and had difficulty getting pregnant. Patric allowed her to use his sperm but expressed reluctance about fatherhood.

They disagree on what happened after Gus, now 3, was born — whether they wanted to be together and Patric’s relationship with the boy.

Schreiber has told the media that Patric never changed a diaper and rarely spent time alone with the child. Patric claims to have visited often, contributed financially and bonded with Gus, who — at least sometimes — called him “Dada.”

The legal burden is on Patric. State law provides that a man who donates sperm to a woman not his wife is not a father unless both sign an agreement to the contrary. In contrast, a couple who conceive the old-fashioned way are both parents, no matter what agreement they sign.

A distinction between biological progenitors who use a doctor and therefore are not parents under the law (even if they assume the role) and those who conceive without a doctor and are legal parents even if they have no relationship with the child makes no sense. California courts have rejected such a distinction in the case of egg donors.

In a dispute similar to the Patric-Schreiber one, the California Supreme Court focused on who functioned as a parent.

When K.M. donated her eggs to her partner, she signed an agreement in which she promised not to claim any parenthood rights. After twins were born, K.M. lived with her partner and the children for five years. When they broke up, K.M. sought to remain involved in their children’s lives.

A lower court made an analogy between K.M.’s status and that of a sperm donor who was not a parent. Then, in 2005, in one of a groundbreaking trilogy of cases in which the California high court recognized the possibility of two mothers, the court ruled that, because the parties intended to raise the children in their joint home and actually did so, K.M. was a parent. Indeed, the donor provision of California law (that prevents Patric from claiming to be a parent) simply did not apply to this situation.

We suspect that if Patric and Schreiber had in fact raised the child together for a significant period of time, the court would have recognized his paternal status with or without an agreement.

SB 115, however, while it appears to simply extend the K.M. case to men, in fact introduces more uncertainty in the determination of parenthood. It does nothing to encourage prospective parents to reach accord before the child is born or to take children’s interests into account afterward. And it has no standard for determining how much involvement is necessary before a sperm donor can claim to be a parent, encouraging litigation that may favor wealthier or more powerful parties such as Patric.

The legislation, however, does send a clear message to new mothers: Do not encourage the involvement of another adult if you are not willing to potentially share custody later.

Naomi Cahn is a professor at George Washington University Law School. June Carbone is a professor at the University of Minnesota Law School. They wrote this for the Los Angeles Times.

– McClatchy-Tribune Information Services