The issue of childhood sexuality is controversial, and one which makes many people uncomfortable. But, although childhood sexuality is very different to that of the mature adult, there is little doubt that humans are sexual beings from birth, and even before: boy babies can have erections while still in utero, and some boys are born with an erection. Toddlers, and even babies as young as three to five months old might touch their genitals. Parents can be assured that this activity is quite normal, and that the child finds it soothing and relaxing.
Pre-school boys are curious about their bodies, and are interested in and aware of gender differences, such as male and female genitals and how boys and girls urinate. They may mimic adult social and sexual behaviours, such as holding hands and kissing. Boys of this age may role-play or talk about being married or having a partner. It is not uncommon for young children to touch or play with their genitals or to play games, such as “doctor” that include sexual exploration. This is a natural way for children to explore their bodies, and boys may experience orgasm from masturbation although they will not ejaculate until puberty. Generally by the age of about five or six, become more aware of social restrictions on sexual expression, and develop a sense of privacy.
Puberty, the set of physiological changes that results in physical sexual maturity, begins between age 10 and 14 in boys. The testicles and penis get bigger, pubic body and facial hair grows, the voice deepens, and secretions from the oil and sweat glands increase. There is also a general growth spurt. Erections increase in frequency, and first ejaculation typically occurs between ages 11 and 15.
The ability to produce sperm may take another year or two. These changes are accompanied by a surge of interest in sex. During this period, boys gain further experience with masturbation: about half of all boys have masturbated to orgasm by age 13. Because preadolescents tend to spend time mainly with others of their own sex, it is not uncommon for early sexual exploration to occur with other boys. By age 12 or 13, some boys will have started dating and "making out" with girls, but overt sexual activity with the opposite sex is still unusual.