BELMONT, Calif. — Sex education in many American high schools is evolving to include instruction of the “yes means yes” standard for seeking and giving consent during intimate encounters. 

After taking hold on college campuses, the standard also known as affirmative consent is trickling down to high schools and even some middle schools, as educators seek to give students tools to combat sexual violence.

“Yes means yes” means sex is consensual only when both partners are sober and clearly state their willingness to participate through “affirmative, conscious and voluntary agreement,” every step of the way.

California is the first U.S. state to require “yes means yes” instruction in public high schools, starting next year. Around the country, nearly two dozen bills introduced in statehouses this year covered instruction in healthy relationships, communication or consent.