However, lead author Rebekah Levine Coley of Boston College said the findings were only "suggestive ... not definitive" and did not reveal which parenting techniques work the best.

Coley noted that more than two out of every three U.S. teens has sexual intercourse before age 19. However, she didn't provide specific statistics for teens with parents who are more "democratic."

Coley and her colleagues examined the results of an annual survey of 4,980 American teens born between 1980 and 1984, and used statistical techniques to try to pinpoint the effects of parenting styles.

The findings, reported in the August issue of the Journal of Adolescent Health, found that children seemed to be less sexually active if their parents did not engage in negative and psychologically controlling behaviors. Things such as family dinners, fun activities or religious activities together seemed to make sexual activity less likely, the findings indicated.

"Warm, more democratic relationships -- in which parents do not use negative and psychologically controlling behaviors -- could help parents to communicate values, increase adolescents' identification with their parents, help youth to develop healthy decision-making skills and also keep youth away from negative peer influences," Coley said in a statement.