Fathers' attitudes toward teen sex and the emotional closeness of their relationship with their teens have a sizable influence on their teens' sexual behavior, separate from the influence of moms, a new review of studies suggests.
The review showed that dads' attitudes toward teen sexual behavior were linked to the age at which teens first had sex. Teens whose dads approved of adolescent sexual activity tended to start having sex earlier than teens whose dads did not approve, according to studies in the review.
In addition, teens who were close to their fathers tended to start having sex later, the studies showed.
The findings "suggest that fathers may distinctly influence the sexual behavior of their adolescent children," said study researcher Vincent Guilamo-Ramos, a professor of social work at New York University. "Fathers may parent in ways that differ from mothers, and therefore represent an additional opportunity to support adolescent health and well-being," he said.
A better understanding of the role dads play in their teens' sexual behavior and reproductive health could help researchers identify which parenting practices have the biggest impact on teens and lead to better intervention strategies that include both moms and dads, the researchers said.
A 2011 survey by the Centers for Disease Control and Prevention showed that 47 percent of high school students had ever had intercourse, and 40 percent of those who were sexually active did not use a condom when they last had sex.
Adolescence is generally a time of increased risk-taking, and with sexual activity, such risk-taking can be bad for teens' health, Guilamo-Ramos said. It can lead to sexually transmitted infections and unwanted pregnancy.
Previous studies have linked positive parent-teen relationships with teens' sexual behavior. For example, researchers have shown that parents who monitor and discipline their teens and communicate with them reduce the risk of their teens' being involved in sexually risky behaviors.
However, most studies have focused on the influence of mothers on teens' behavior.
In the new review, Guilamo-Ramos and colleagues looked at 13 studies of the paternal influence on the behavior of teens between ages 11 and 18. The researchers defined "fathers" broadly -- they included biological fathers, stepfathers and adoptive fathers, and other men such as uncles or grandfathers who participated as primary male caregivers in teens' lives.
In considering the effect of a dad's general levels of strictness, a few studies showed that teens of both overly restrictive and overly lenient fathers started having sex earlier than teens of moderately strict fathers.
"Fathers who are moderately strict are those that have clear rules and agreed-upon rational consequences that have been discussed with their teen children," Guilamo-Ramos said. Teens should understand their fathers' expectations and know the consequences of not following the rules. But fathers should also discuss with their teens the decisions teens can manage on their own and the areas where fathers want input from their teens in making a rule or decision, he said.
Encouraging appropriate levels of teen autonomy and being consistent are important actions for fathers, he said.
"Evidence increasingly suggests that mothers and fathers independently shape areas of child development, such as academic success and peer relationships," the researchers wrote in the study, published in the journal Pediatrics.