What is a common cause of gynecomastia during puberty in boys?

During puberty, boys undergo significant hormonal changes that are a normal part of development. These changes typically involve fluctuations in levels of testosterone and estrogen. Gynecomastia, which is the enlargement of breast tissue in males, is often observed during this phase because of the relative increase in estrogen levels compared to testosterone.

This condition can occur due to the normal physiological processes as the body adjusts to changes in hormone levels, leading to transient breast tissue development. It is a common occurrence and usually resolves on its own as hormone levels stabilize.

Other options, such as increased testosterone, decline of estrogen, and excessive exercise, do not directly relate to the typical hormonal shifts that cause gynecomastia during puberty. Instead, they either imply an increase in testosterone or suggest factors that are not typically responsible for this condition in the context of normal adolescent development. Understanding that gynecomastia during puberty is a part of normal hormonal development helps to contextualize this condition in adolescent boys.