In late 2004 the Internet Movie Database reported that Dustin Hoffman suddenly had the urge to breast-feed. Had the then-67-year-old Hoffman—who brought mainstream culture face to face with autism in Rain Man and went mano a mano with an Ebola-like filovirus in Outbreak—never quite broken character from his 1982 film Tootsie? Nope. He was just really keen to help out with his first grandchild.



Interestingly, he could have possibly lent a helping, er, breast, if he had held the suckling newborn to his nipples for a couple weeks although he could also have tried starving himself or taking a medication that would affect his brain's pituitary gland.



There have been countless literary descriptions of men miraculously breast-feeding, from The Talmud to Tolstoy, where, in Anna Karenina, there is a short anecdote of a baby suckling an Englishman for sustenance while on board a ship. The little anthropological evidence documented suggests it is possible. In the 1896 compendium Anomalies and Curiosities of Medicine, George Gould and Walter Pyle catalogue several instances of male nursing being observed. Among them was a South American man, observed by Prussian naturalist Alexander von Humboldt, who subbed as wet nurse after his wife fell ill as well as male missionaries in Brazil that were the sole milk supply for their children because their wives had shriveled breasts. More recently, Agence France-Presse reported a short piece in 2002 on a 38-year-old man in Sri Lanka who nursed his two daughters through their infancy after his wife died during the birth of her second child.



In her 1978 book The Tender Gift: Breastfeeding, medical anthropologist Dana Raphael claimed that men could induce lactation simply by stimulating their nipples. The eminent endocrinologist Robert Greenblatt of the Medical College of Georgia concurred. But Jack Newman, a Toronto-based doctor and breast-feeding expert, insists that in order to produce milk, a hormone spike must occur. "That Tolstoy quote suggests that the father just put the baby to the breast and he would produce milk; I think that's pretty unlikely," he says. "It could be that you have this man with this pituitary tumor and he produces milk once the baby starts suckling."

Newman explains that medical disruptions involving prolactin, the hormone necessary to produce milk, have resulted in spontaneous lactation. Thorazine, a popular antipsychotic used in the mid-20th century, impacted the pituitary gland—the pea-size endocrine gland located near the base of the brain—often causing it to overproduce prolactin. If prolactin levels remained high, milk could follow. According to Newman, lactation is listed as a possible side effect of the heart medication digoxin. A pituitary tumor could also induce milk production: "It would be the same reason—increased prolactin levels—the one case drug-induced, in the other due to a tumor or some other sort of neurological problem."



In a 1995 article for Discover titled "Father's Milk," Pulitzer Prize-winning author and one-time physiologist Jared Diamond reconciles the nipple stimulation and hormone quandary, pointing out that such stimulation can release prolactin. He also notes that starvation—which inhibits the functioning of hormone-producing glands as well as the hormone-absorbing liver—can cause spontaneous lactation, as observed in survivors of Nazi concentration camps and Japanese POW camps in World War II. "The glands recover much faster than the liver when normal nutrition is resumed," he writes, "so hormone levels soar unchecked."



Males of many different mammalian species have the potential to lactate, although only one, the Dayak fruit bat of Southeast Asia, does so spontaneously. Diamond points out, however, that with the societal norm of fathers helping to rear their young, male milk production could actually be to our advantage, especially with all the career women trying to balance the demands of job and family. Why else would men still have nipples?



"Up until a certain age, boys and girls, as fetuses, are indistinguishable, really, so women retain some remnants of the vas deferens, which is the canal that sperm follows," Newman answers. "If you have no Y chromosome, then certain hormones are released that say, 'Okay, we'll set up this child's breast tissue to develop at puberty so that she will be able to produce milk.' Men didn't [secrete those hormones], so we don't usually have breast tissue."



"Actually a significant number of boys around the age of puberty do develop breasts," he continues, "so the tissue is there, but it regresses." In short, men may not have full-fledged breasts but they certainly can lactate, under extreme circumstances.