SACRAMENTO (AP) — California children could have more than two legal parents if a bill speeding through the Legislature becomes law.

The bill by Sen. Mark Leno, D-San Francisco, would allow judges to recognize multiple parents in cases where children would be best served by several parental relationships. All parents would still have to meet existing standards for legal parenthood.

Leno has characterized the bill as a response to America’s evolving families. Married couples dropped below half of all American households for the first time in 2010, according to the Census Bureau.

Several other states, including Pennsylvania and Maine, recognize more than two parents.

Supporters cited several examples where the law could be applied, including a lesbian couple that conceived a child with the help of a sperm donor who has been involved as a parent, or a man who married a woman while she was pregnant with another man’s child, who also maintained his role a father.

They also say the bill could keep some children out of foster care by establishing additional parents with caretaking and financial responsibility.

Opponents fear there could be no limit to the number of parents a child could have.

“Because parentage law is so complicated, it is difficult to attempt to change one aspect of it without upsetting the entire framework,” the Association of Certified Family Law Specialists wrote in a letter of opposition.

They also say Leno’s bill could undermine conservative family values.

“He’s trying to change the whole attitudes and understanding of what family is,” California Right to Life Committee Director Camille Giglio said. “Family is a father and a mother and children.”

Supporters say it is unlikely the number of parents would proliferate because the bill does not change the definition of parenthood or allow temporary caretakers such as boyfriends or girlfriends to be considered as parents.

Instead, SB1476 involves families in which more than two adults take a child into their home and present the child as their own, not as a step-child.

Backers dismissed moral concerns, saying the bill is a simple modernization of family law.

“It’s not us who have changed the nature of families; families have done it on their own,” said Ed Howard, senior counsel for the Children’s Advocacy Institute at the University of San Diego School of Law. “It is cruel to prevent judges from ruling a way that protects kids in favor of an abstraction of what a family used to look like.”

The Senate has approved the bill and it is working its way through policy committees in the Assembly.

(Copyright 2012 The Associated Press.)