If there is a family history of gynecomastia, it is possible to inherit the condition, but not always. Sometimes one brother could inherit it and not another.
There are some genetic conditions such as Klinefelter’s syndrome and Gilbert’s syndrome that can cause the development of the male breast. The more common inherited cause is hormonal imbalance occurring in boys ranging in age from 12 to 18. For these boys, generally it settles down when they pass puberty. For a small percentage, it will persist for life, leaving gynecomastia surgery, or moob reduction surgery, as the only option for reduction.
For Sacramento men developing gynecomastia breasts in their adult years, it could be due to medications they may be taking. Gynecomastia.org has a comprehensive list of drugs that have been known to cause man boobs or “moobs” for some men.