She also faces a sentencing enhancement for substantial sexual conduct with a child.
Serrano is accused of having sex with the 12-year-old boy in her home and in a car last month.
"She met this little boy because he was friends with her son," said Farrah Emami, spokesperson for the Orange County District Attorney's Office.
Prosecutors suspect Serrano of sexually assaulting the boy in her home in Fountain Valley and in her car.
Prosecutors allege on another occasion Serrano was kissing the boy in a locked room. The boy's mother tried to get in. She did not see any sexual contact but she was suspicious enough to go to police.
Investigators say the alleged acts began last month and ended with her arrest earlier this week.
Authorities are concerned there may be other potential victims.
"She was having sex with a 12-year-old boy. She has a child that's around the same age. She has access to other children, and we really hope that there aren't other kids out there who have experienced a similar sexual assault," said Emami. "If there are we would encourage them to come forward."
Serrano was arrested on Tuesday and was being held on $100,000 bail.
If convicted, she faces up to 12 years in prison.
If you have information about the case, contact the Orange County District Attorney's Office at (714) 347-8794.