PITTSBURGH (AP) — The Pennsylvania Interscholastic Athletic Association has overhauled gender rules for boys and girls sports teams, which will make it nearly impossible for boys to play on girls' squads.

The Pittsburgh Post-Gazette (http://bit.ly/1oMYdO4 ) reports the rule changes were approved Thursday.They were prompted largely by instances in which boys were playing field hockey or volleyball — traditionally girls' sports — because their schools didn't offer those teams for boys.Under the new rules, boys can still play on girls teams, but only if the school's principal determines four things:The boy wouldn't displace a girl from the team; wouldn't increase the risk of injury to opponents because of his size; wouldn't provide a significant competitive advantage; and if the overall sports program at a school provides fewer opportunities for boys than girls.