adolescent gynecomastia: in about 15 percent of boys at puberty, the growth of glandular tissue and enlargement of the breasts in response to the hormones of puberty. Typically the enlargement is minimal and self-correcting, but in rare cases resembles that of a girl and requires corrective plastic surgery (mastectomy). The etiology, though obscure, is attributed either to an atypical utilization of the low level of estrogen normally produced by the testicles of the male, or to an atypical resistance to the counteracting effect of testosterone.

Dictionary of Sexology Project: Main Index