Either women or men have little control over the size of their chest. Ideally, a man’s chest is rock hard muscle or bony from the rib cage. However about 30 percent of men, according to a study in the Indian Journal of Endocrinology and Metabolism, tend to grow a pair of “man boobs” at some age in their lives.
The technical term used is gynecomastia, which is a hormone expert Rob Kominiarek, D.O., medical director of ReNue Health in Springboro, Ohio, says, development of full chest on a man, from the congenial swelling of breast tissues typically caused by an imbalance in hormones. When hormones are in their natural flux, men often start developing breasts. This happens mostly during puberty or old age (since the likelihood for gynecomastia starts going up around 50). However, otherwise too, “man boobs” can develop at any age.