Sexual Activity and Youth

Studies show that the number of lifetime sexual partners for both males and females is directly related the age of first intercourse.Young people who participate in first intercourse before age 14 are significantly more likely to have more lifetime sexual partners. Fifty-seven percent of girls who initiate sex before age 14 report six or more lifetime partners compared to 10 percent of girls who initiate sex at age 17 or older.  Likewise, 74 percent of boys who initiate sex before age 14 report six or more lifetime partners compared to 10 percent of boys who initiate sex at age 17 or older.

All the study here