Is an increase in sexual activity during adolescence a normal part of the transition to adulthood, or evidence of a societal problem? Why would conservative religious youth become sexually active earlier than their peers and be more likely to have an unintended pregnancy or sexually transmitted disease? How are women continuing to lead our society's sexual transformation?

Written by an author whose 40-year career in sexology and university administration provides a uniquely qualified perspective upon both sex research and the changing sexual perceptions of American youth, this...