You might believe that only women can breastfeed, but that is incorrect. In reality, anyone, even those who are not pregnant or nursing, can produce milk. This includes men.
Male lactation is possible due to hormonal imbalances caused by various factors, such as starvation, liver disease, pituitary tumors or medication side effects. These conditions can increase the levels of prolactin, the hormone that stimulates milk production, in the blood.
Male lactation is usually a sign of an underlying medical problem that shouldn’t be ignored. But in some rare cases, it can happen spontaneously or intentionally.
Alexander von Humboldt was fascinated by male lactation. In his book, Voyage aux régions équinoxiales du Nouveau Continent, he tells the story of a man from the Venezuelan village of Arenas (near Cumana) who allegedly nursed his son for three months when his wife was ill.
Charles Darwin also commented on male lactation in The Descent of Man, and Selection in Relation to Sex (1871): “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.”
Male lactation is common in dayak fruit bats, but rare in other animals. However, some domesticated animals, such as cats, goats and guinea pigs, have been observed to lactate on rare occasions.
Male-to-female transsexuals may also produce milk due to the hormones they take to reshape their bodies.
But before you get too curious about male lactation, remember that it is not a natural or healthy phenomenon for most men. It can indicate serious health issues that need medical attention. And it can also have psychological and social consequences for men who feel embarrassed or ashamed of their condition.