Typical Age Range
This stage starts at the first signs of puberty and ends when the adolescent growth spurt begins. On average it starts around age 11, but can start as early as 9 or as late as 15. It typically lasts about two years.
Characteristics and Changes During Stage 2:
Hormones
Puberty marks the beginning of this stage, though outward signs do not appear immediately. Puberty officially is the rise of gender-specific hormones above typical childhood levels.
Growth
During this stage growth continues at a rate of about two inches (5 to 6 cm) per year.
Genitals
Scrotum begins to swell and reddens color. The skin of the scrotum becomes thinner. Testes are between 1 and 1 1/4 inches (2.5 to 3.2 cm) measured along the long axis or measured in volume they are 1.6 to 6 ml.
The penis begins increasing in both length and width a bit. Spontaneous erections begin in this stage. About half of all boys gain the ability to ejaculate semen in the latter part of this stage.
Hair
Fine, lightly pigmented (downy) hairs form around the base of the penis and under the arms.
Body
A ring (the areola) forms around the nipples on the chest.
Toward the end of stage 2 the hands and feet become larger and out of proportion to the rest of the body.