According to several studies, women between the ages of 27 and 45 report the highest interest in sex and more sexual fantasies than women in other age groups. Women also report having more sex during these years than women of other ages. However, its important to note that there is no absolute time when people have a sexual peak, and the ongoing research on human sexuality indicates a wide variety of sex drives. While testosterone levels are high in mens 20s, sex drive generally is as well. In males, testosterone levels peak at around age 17 and then gradually decline. In general, sex drive does often decrease with age, but its not a hard and fast rule.