Sen. Joel Anderson, R-Alpine, said he opposed the bill because verification would be too burdensome for social networking companies to verify a user and his or her parent.
"I know for a fact that this bill is not fully cooked," Anderson said.
While the bill passed mostly on party lines, Sen. Jerry Hill, a Democrat from San Mateo, voted no, and several Democrats abstained from the vote.
The bill is supported by law enforcement groups such as the California State Sheriff's Association and the Peace Officers Research Association of California. It also has support from child abuse prevention groups.