Californian lawmakers passed a law requiring universities to adopt "affirmative consent" language in their definitions of consensual sex, part of a nationwide drive to curb sexual assault on U.S. campuses.

The measure, passed unanimously by the California State Senate, has been called the "yes-means-yes" bill. It defines sexual consent between people as "an affirmative, conscious and voluntary agreement to engage in sexual activity", says Reuters. 

The bill states that silence and a lack of resistance do not signify consent and that drugs or alcohol do not excuse unwanted sexual activity, Reuters reports. 

Governor Jerry Brown must sign the bill into law by the end of September. If he does, it would mark the first time a U.S. state requires such language to be a central tenet of school sexual assault policies, said Claire Conlon, a spokeswoman for State Senator Kevin De Leon, who championed the legislation, says Reuters. 

Opponents of the bill say it is politically over-reaching and could push universities into little charted legal waters.

Universities in California and beyond have already taken steps, including seeking to delineate whether consent has been given beyond 'no means no'.

Under California's bill, state-funded colleges and universities must adopt strict policies regarding sexual assault, domestic violence, dating violence and stalking, among other actions in order to receive financial aid money.

The U.S. Department of Education in May released a list of 55 colleges -- including three in California -- under investigation to determine whether their handling of sex assaults and harassment violated federal laws put in place to ensure equal treatment in higher education.

The Californian institutions on the list are University of California, Berkeley, Occidental College and the University of Southern California.

http://www.reuters.com