In zoology, male lactation is the production of milk physiological development of boys a male mammal’s mammary glands in the presence of physiological stimuli connected with nursing infants. Such production is known as lactation. It is well known that in the males of all mammals, including man, rudimentary mammae exist.
These in several instances have become well developed, and have yielded a copious supply of milk. Their essential identity in the two sexes is likewise shown by their occasional sympathetic enlargement in both during an attack of the measles. Darwin later considered the nearly perfect function of male nipples in contrast to greatly reduced structures such as the vesicula prostatica, speculating that both sexes may have nursed young in early mammalian ancestors, and subsequently mammals evolved to inactivate them in males at an early age. Male mammals of many species have been observed to lactate under unusual or pathogenic conditions such as extreme stress, castration and exposure to phytoestrogens, or pituitary tumors. Therefore, it is hypothesized that, while most male mammals could easily develop the ability to lactate, there is no selective advantage to male lactation.
Human male breastfeeding is possible, but production of the hormone prolactin is necessary to induce lactation, so male lactation does not occur under normal conditions. Domperidone is a drug that can be used to increase lactation. Spontaneous production of milk not associated with childbirth, known as galactorrhea, can occur in males and females. Voyage aux régions équinoxiales du Nouveau Continent : fait en 1799, 1800, 1801, 1803 et 1804. Male lactation: why, why not and is it care? Structural and Ultrastructural Study of GH, PRL and SMT Cells in Male Goat by Immunocytochemical Methods”.