NEW YORK (Reuters Health) - Sex education in school may encourage teenagers to put off having sexual intercourse, the results of a U.S. government study suggests.

The study, published Wednesday in the Journal of Adolescent Health, did not whether the type of program matters -- that is, abstinence-only versus more-comprehensive programs.

However, the findings do suggest that having some form of sex education helps delay teen sex, according to the researchers, from the Centers for Disease Control and Prevention (CDC) in Atlanta.

In a national survey of more than 2,000 adolescents between 15 and 19 years old, the researchers found that teens who had sex ed in school were more likely to put off sex until at least age 15. Furthermore, boys who received sex ed were less likely to have started having sex at all.

“Sex education seems to be working,” lead researcher Dr. Trisha E. Mueller, an epidemiologist with the CDC, said in a statement.

In particular, she noted, some of the greatest benefits were seen in the teens who may need them the most -- urban, African-American girls. In this group of girls, those who’d received sex education were 91-percent less likely to have had sex before age 15 years.

Overall, male study participants who’d received sex education were 71 percent less likely to have had sex before age 15 than those who’d had no formal sex ed. Among female participants, sex ed reduced those odds by 59 percent.

Male respondents who’d had sex education were more likely to say they would used birth control the first time they had sex. No similar effect was seen among girls.

There were certain groups of teens who did not seem to benefit from sex education. Girls from rural areas were more likely to have ever had sex when they’d received sex education; and among white and Hispanic girls who eventually dropped out of high school, those who received sex ed were less likely to delay having sex.

The reasons are unclear, according to Mueller’s team, and the findings may be due to chance because the numbers of study participants in these groups were small.

“Sex education,” they conclude, “provides youth with the knowledge and skills to make healthy and informed decisions about sex, and this study indicates that sex education is making a difference in the sexual behaviors of American youth.”

SOURCE: Journal of Adolescent Health, January 2008.