Approximately one in five adolescents has had sexual intercourse before his or her 15th birthday, according to this report. It also notes that one in seven sexually experienced 14-year-old girls reports having been pregnant. Parents are usually unaware if their young adolescents have had sex. Only about one-third of parents of sexually experienced 14-year-olds know that their child has had sex. And while the majority of parents say they have spoken to their young adolescent children about sex, far fewer teens report that such conversations actually took place. The report is the work of seven teams of investigators examining three nationally-representative data sets and three smaller area data sets. While each data set was collected at different times and in different ways, a surprisingly consistent picture emerges of sexual relationships and activity among very young teens.