The receptor-hormone complex then binds to DNA promoting gene transcription. In some target cells testosterone is converted within the cytoplasm to DHT which has a greater affinity for the same intracellular receptor. DHT-receptor complexes are necessary to the formation of male external genitalia in early development , enlargement of the prostate and penis , and hair growth at the time of puberty. The age at the time of puberty is variable. US boys usually experience puberty between the ages of 9 and 14.
Androgens induce the following changes in boys at the time of puberty.
Penis enlarges in length and width. Scrotum becomes pigmented and wrinkled. Seminal vesicles, prostate and Cowper's glands enlarge and secrete. Larynx enlarges, vocal cords increase in length and thickness causing the voice to become deeper. Hair appears in arm pits, on chest, and around anus.