The National Women's Law Center filed administrative complaints Wednesday against the Irvine Unified School District, asserting that administrators did not provide equal opportunity to girls in sports.
The advocacy group claims that Irvine Unified is among those nationwide in violation of Title IX.
The center filed complaints with the U.S. Department of Education's Office for Civil Rights against 12 school districts for allegedly not adhering to the federal law that prohibits sex discrimination in federally funded education programs.
"The allegation is certainly puzzling," said Ian Hanigan, public information officer for the Irvine Unified School District. "We have great respect for Title IX, and we do provide equal opportunities for girls who wish to participate in athletics."
The school district withheld further comment pending review of the complaint and further investigation.
The news comes at something of an odd time for the district.
At the Irvine City Council meeting Tuesday night, city staff announced that Irvine was selected as one of the 100 Best Communities for Young People by America's Promise Alliance. The national competition identifies 100 communities that have demonstrated their commitment to ending the high school dropout crisis by helping young people overcome challenges to succeed.
This 2010 recognition marks the third time for Irvine, according to a city press release.
In Irvine Unified, there is a 10.6% gap between the percentage of girls enrolled and the percentage of girls who are athletes. The participation gap worsened between 2000 and 2006, according to information from the center.
Under Title IX, schools are required to demonstrate adherence to at least one of a three-part participation test, said Neena Chaudhry, senior counsel for the center.
A school must demonstrate that: The percentage of male and female athletes roughly equals that of the percentage enrolled; there is a history and continuing practice of expanding opportunities for girls; or that school programs are fully accommodating to the interest of girls.
Under Title IX, schools are required to provide an equal opportunity for participation, but not necessarily the same sports for both girls and boys. Some sports, such as football, remain to be played primarily by boys, Chaudhry said.
Irvine Unified does not offer girls several sports sanctioned by the California Interscholastic Federation, such as hockey, gymnastics, badminton and skiing, and there is no reason to believe that high school girls in the district are any less interested in these sports than other girls in the state, according to the complaint filed by the center.
"These  districts are examples of a much larger problem," Chaudhry said. "We're hoping that it is a wake up call for schools across the county."