MONDAY, Aug. 1 (HealthDay News) -- A new nationwide look at data on masturbation among U.S. adolescents finds that boys do it much more often than girls, and they also tend to start earlier.

In addition, masturbation in adolescence appears to be tied to other types of behavior, including both a greater likelihood of engaging in sexual relations with a partner and increased condom use.

The finding is based on an analysis of 2009 data on sexual behavior involving more than 800 teens, aged 14 to 17 years, responding to the National Survey of Sexual Health and Behavior (NSSHB).

"Much attention today is given to adolescent sexuality, but few studies have focused on masturbation," noted study lead author Dr. Cynthia L. Robbins, from the section of adolescent medicine in the department of pediatrics at Indiana University in Indianapolis. "Many adolescent boys and girls masturbate, and among sexually active teens masturbation is associated with other sexual behaviors and condom use," she said.

"It is important to recognize that masturbation is an important and normal component of adolescent sexual development," Robbins added.

Her team reported their findings online Aug. 1 in the Archives of Pediatrics and Adolescent Medicine.

With parental permission, the NSSHB survey asked both male and female adolescents (as well as their adult guardians) to recall how often they had masturbated over the prior three months, over the past year, and over the course of their lifetime. Those polled were also asked how often they masturbated alone versus with a sexual partner. Condom use was also noted.

The results: boys were found to masturbate more often than girls, both overall and across all measured time frames.

For example, while nearly three-quarters of boys surveyed reported having ever masturbated, that figure was slightly less than half among girls.

For both sexes, the likelihood of engaging in masturbation appeared to increase with age. Among boys between the ages of 14 and 17 the percentage of those who had masturbated at least once rose from about 63 to 80 percent. Among girls, those figures were lower but still followed an upward slope, rising from about 43 percent to 58 percent across the same time-frame, according to the report.

Yet while boys also were increasingly likely to say they had "recently" masturbated as they got older (rising from 43 percent at the age of 14 to almost 68 percent among 17-year-olds), the same observation was not made among girls.

Boys also engaged in masturbation more frequently than girls: about half of the boys said they engaged in the activity at least twice a week, but that figure fell to about 23 percent among girls. An estimated 46 percent of girls reported masturbating only a few times per year.

In addition, for both boys and girls, engaging in masturbation was associated with a greater odds of engaging in sexual relations with a partner, compared to adolescents who did not masturbate. For boys, masturbation was linked to higher odds of engaging in oral sex and vaginal intercourse, while for girls it was linked to higher odds for oral sex, partnered masturbation, and both vaginal and anal intercourse.

Lastly, the study authors found that condom use was linked to masturbation among those boys (but not girls) who also engaged in vaginal intercourse.

Robbins and her team concluded that "the association of masturbation with other sexual behaviors indicates that masturbation is an important component of adolescent sexuality rather than an isolated or transient phenomenon." In that regard, they urge that teens be educated and reassured that the act is a "normal" part of growing up.

Commenting on the study, Alan Hilfer, director of psychology at Maimonides Medical Center in Brooklyn, N.Y., said he supports the notion that teens should be encouraged to develop a view of masturbation that is free of fear or concern.

"It goes without saying that we should help teens, boys and girls, be comfortable with this. And we should understand while doing this that there is certainly a gender difference, in that girls, for better or worse, are still far more reserved than boys on both the subject and the act," he said.

"And that means, of course, that in terms of the main finding that teenage boys engage in this more than girls, I am absolutely not shocked or surprised," Hilfer added. "I think that testosterone is a big factor among boys. And I think that it's more socially acceptable among their peer group in general to talk about it and engage in it. It is becoming more acceptable among girls. But historically, and still today, it's something that boys do more and earlier."

More information

There's more on this topic at the American Academy of Pediatrics.