MINNEAPOLIS (AP) — A nonprofit legal foundation is threatening to sue the Minnesota State High School League on behalf of a 15-year-old Wisconsin boy who was barred from participating in a girls' high school dance championship last December.

The Pacific Legal Foundation sent a letter Tuesday to the high school league, setting a Nov. 3 deadline for Kaiden Johnson to be allowed to dance.

Johnson is on the team at Superior High School in northwestern Wisconsin. It competes against teams from Minnesota, where only girls are allowed to dance competitively.

Attorney Joshua Thompson of the Pacific Legal Foundation calls that "a classification based on 1970s ideals about what boys should be doing and what girls should be doing."

High school league executive director Dave Stead said the league won't comment on threatened litigation.