The availability of new and more effective forms of birth control was a key underpinning of the sexual revolution. The notion of "recreational sex" without the threat of unwanted pregnancy radically changed the social dynamic and permitted both women and men much greater freedom in the selection of sexual lifestyles outside the confines of traditional marriage. With this change in attitude, by the 1990s the ratio of children born out of wedlock rose from 5% to 25% for Whites and from 25% to 66% for African-Americans.