AbstractSocieties socialize children about sex. This is done in the presence of peer-group effects, which may encourage undesirable behavior. Parents want the best for their children. Still, they weigh the marginal gains from socializing their children against its costs. Churches and states may stigmatize sex, both because of a concern about the welfare of their flocks and the need to control the cost of charity associated with out-of-wedlock births. Modern contraceptives have profoundly affected the calculus for instilling sexual mores. As contraception has improved there is less need for parents, churches and states to inculcate sexual mores. Technology affects culture.