Young males who have been sexually abused are five times more likely to cause teen pregnancy compared to those with no abuse history, according to University of British Columbia research.

Sexually abused boys are also three times more likely to have multiple sexual partners and twice as likely to engage in unprotected sex.

Published online in advance of the Journal of Adolescent Health's June issue, the UBC study explores links between sexual abuse and risky sexual behaviour, focusing on three areas: teen pregnancy, multiple sexual partners and unprotected sexual intercourse.

The researchers analyzed 10 sets of Canadian and U.S. survey data from two decades of published studies. Conducted between 1986 and 2011, the surveys were completed anonymously by more than 40,000 male high school students in B.C. and across the U.S., including states such as Oregon, Vermont, Minnesota and Massachusetts.

"As far as we know, this is the first study to explore the strength of the effects of sexual abuse on boys' sexual behaviour," says lead author Yuko Homma, a recent PhD graduate from the UBC School of Nursing.

"Our findings show that, boys are also vulnerable to the traumatic effects of sexual abuse, which can lead to sexually transmitted infections or teen pregnancy."

Homma advises, "Parents need to speak to their sons about sexual abuse awareness and prevention, as parents of girls do. Boys may hesitate to tell parents about an incident if parents have misconceptions about sexual abuse - that it can't happen to males."

The researchers recommend that schools include sexual abuse prevention in health education and that health care agencies screen for sexual abuse histories among boys and girls.

"Boys are far less likely to tell someone when they have been sexually abused," says co-author Elizabeth Saewyc, UBC professor of nursing and adolescent medicine. "Yet it's clear they too need support and care to cope with the trauma from sexual violence."

On average, about eight per cent of males and 20 per cent of females in North America report a history of sexual abuse.