New research reveals that sexual double standard starts in the early teens, Medical Daily reported.

Researchers found that early adolescent girls lose friends for having sex and gain friends for "making out," while their male peers lose friends for "making out" and gain friends for having sex.

"In our sample of early adolescents, girls' friendship networks shrink significantly after they have sex, whereas boys' friendship networks expand significantly," Derek A. Kreager, lead author of the study and an associate professor of sociology and criminology at Pennsylvania State University, said in a statement. "But what really surprised us was that 'making out' showed a pattern consistent with a strong reverse sexual double standard, such that girls who 'make out' without having sex see significant increases in friendships, and boys who engage in the same behavior see significant decreases in friendships."

For the study, researchers collected and analyzed data from more than 900 students between the ages of 11 and 16 who completed in-home surveys that included measures of sexual behavior, CBS Chicago reported. As part of study, students were asked to nominate their best or closest friends in the same grade. In order to identify changes in peer acceptance, Kreager and his colleagues considered how many friendship nominations participants received in each wave.

They found that in waves where they reported having sex, on average, girls experienced a 45 percent decrease in peer acceptance and boys experienced an 88 percent increase. On the other hand, in waves where they reported "making out" without having sex, on average, girls experienced a 25 percent increase in peer acceptance, while boys experienced a 29 percent decrease in peer acceptance.

"Our results are consistent with traditional gender scripts," Kreager said. "Men and boys are expected to act on innate or strong sex drives to initiate heterosexual contacts for the purpose of sex rather than romance and pursue multiple sexual partnerships. In contrast, women and girls are expected to desire romance over sex, value monogamy, and 'gatekeep' male sexual advances within committed relationships. A sexual double standard then arises because women and girls who violate traditional sexual scripts and have casual and/or multiple sexual partnerships are socially stigmatized, whereas men and boys performing similar behaviors are rewarded for achieving masculine ideals."

Kreager found that girls who "defy traditional gender scripts by having sex lose both male and female friendships," Medical Daily reported. However, boys who defy gender scripts by "making out" without having sex usually just lose male friends.

"This pattern suggests that other boys are the peers that police social norms when it comes to masculinity, whereas girls receive strong messages about gender-appropriate sexual behavior from boys and girls," Kreager explained.

The findings will be presented at the 110th Annual Meeting of the American Sociological Association.