ABSTRACT
In pubertal females, a complex hormonal interplay occurs that results in the appearance of the secondary sex characteristics, including the growth and maturation of the adult female breast. Male breast development occurs in an analogous fashion to female breast development, but at a much reduced level due to the markedly lower levels of estrogens in men compared to women. This chapter will review the general ontogeny and physiology of breast development, the factors that influence breast enlargement in the male, the differential diagnosis of gynecomastia, the process of diagnostic investigation, and the treatment of gynecomastia.
