Puberty and Growth - Puberty: changes in boys
The appearance of male sexual characteristics during puberty is also influenced by hormonal changes. But the manifestation of male puberty is somewhat more subtle. The pituitary gland in a boy also secretes a gonadotropic hormone that stimulates maturation of gonads . In the male, the gonads are the testicles , the source of sperm . But whereas maturation of the ovaries in females leads to the menarche, there is no obvious sign in the boy that spermatozoa are being produced.
However, the secondary sexual characteristics, such as the growth of a beard and pubic hair, the spurt of growth of bones and muscles, the increase in size of the sex organs, and the deepening of the voice, are all indications of puberty. The changes in a boy's characteristics during puberty are usually spread over a period of two years, beginning with an increase in the size of the penis and testicles and reaching completion with the production of spermatozoa in the testicles. During the two-year period there usually is a noticeable increase in the chest size of a boy, with the broad shoulders of manhood appearing during the peak of bone and muscle growth. Generally, the appearance of pubic and facial hair, as well as hair in the armpits, follows the growth of the shoulder and chest area and precedes the change in voice.
The testicles are contained in a walnut-size sac of skin called the scrotum . It is held outside the body by a design of nature in order to maintain a temperature for spermatozoa production that is less than internal body temperature. Muscle fibers in the scrotum hold the testicles closer to the body for warmth in cold weather and relax to allow the sperm-producing organ to be farther away from the body when surrounding temperatures are warm.
In some cases, one or both testicles do not descend from the abdomen during the male child's early years. The result is that the undescended testicle or testicles will not produce sperm. An incompletely descended testicle always lies somewhere along the normal path to the scrotum. An ectopic testicle has deviated from that path and lies somewhere near the inguinal canal, at the junction of the thigh and the lower part of the abdomen. In a third departure from normal development, a retractile testicle has stopped short of the scrotum. It can be manipulated into the normal position or may descend to that position at puberty.
The danger of malignant change—of tumor development—usually warrants surgical removal of the incompletely descended and the ectopic testicle. A testicle trapped in the inguinal region may become inflamed because of the pressure of larger body parts in the area. In some cases, physicians are able to assist the descent into the scrotum through administration of hormones or by surgery. At some point during puberty, a medical examination should include a check on the condition of the testes.
Many boys are as sensitive about the size of their genitals as girls are about breast size. In the case of an empty scrotum because of undescended testicles, it is possible to have the scrotum injected with silicone plastic for cosmetic or psychological reasons so the sac appears less flaccid or larger. The size of the penis may become the subject of discussion in the school shower room. If a boy appears sensitive about the subject, he should be assured that there is a wide variation in normal sizes and that like ears, noses, and other body parts the dimensions have little to do with function.
Another cause for concern by adolescent boys is the nocturnal emission . The nocturnal emission, sometimes called a wet dream , is the automatic expulsion of semen through the penis while the young man is asleep. The semen is secreted by the prostate gland , the seminal vesicle , and other glands that open into the urethra . The opalescent white fluid carries spermatozoa during intercourse and if the young male does not engage in sexual intercourse or does not masturbate, the semen simply accumulates until it overflows during a nocturnal emission. It is a harmless, normal occurrence.