Sexual abuse in childhood can lead to high-risk behavior later in life, including early onset of consensual sexual activity (63, 72, 137, 463). For example, in Barbados among a probability sample of 407 men and women, sexual abuse during childhood was the single most important determinant of high-risk sexual activity as a young adult (188). In a recent US study of 535 young mothers, 93% of whom were pregnant by age 17, two-thirds reported having been sexually abused as children. The study found that young women who were sexually abused during childhood began intercourse on average a year earlier than their nonabused peers, were more likely to have used drugs and alcohol, and were less likely to have used contraception (63).

Around the world poverty coerces many young people of both sexes into early sexual activity for money. These young people usually have little bargaining power in their sexual relationships and may be unable to protect themselves from pregnancy and STDs. In Thailand an estimated 800,000 girls under age 20 earn money as prostitutes. In fact, it has become to some an accepted way for young girls to earn money for marriage (225). In parts of Africa some young girls engage in sex with "sugar daddies"—older men who pay school fees or buy clothes and other necessities for them (305, 352, 484).

There are an estimated 40 million street children in Latin America, 25 to 30 million in Asia, and 10 million in Africa, driven from their homes by poverty, abuse, abandonment, or orphaned by AIDS (60, 163). Many street youth are males (38, 404). In Brazil alone some 7 million children and youth live on city streets. Another 10 million work full-time on the streets, many selling sex (60, 225, 403). One Brazilian study found that one-third of women who lived or worked on the street and had had sex said that sex had been forced on them (507). Because street kids are shunned by the community and often have been turned away from public services, these young people tend to be distrustful of the health system and are especially hard to reach with reproductive health services.