Can Men Lactate?


Earlier this month, the United States Supreme Court declined to hear a sex discrimination case from an Iowa woman who wanted to pump milk at work. The Court’s reasoning? It’s not sexist to tell women they can’t lactate at work because men can also lactate.

Which…what? Is it really possible for men to lactate? Can it happen naturally? As it turns out, yes, it can, and it’s more likely in human men than in the vast majority of mammals. That said, don’t worry, fellas. You’re highly unlikely to start sprinkling milk out of the blue.

Let’s start with why women, and not men, lactate routinely in appropriate circumstances. As you might suspect, the cause is genetic—22 of the 23 pairs of human chromosomes are identical, with the 23rd pair the only set that differs between the sexes.

“The genes on chromosome 23, acting in concert with genes on other chromosomes, ultimately determine all differences between our sexes,” wrote Pulitzer Prize winner and one-time physiologist Jared Diamond in a 1995 article for Discover. “Those differences, of course, include not only the possession of ovaries as opposed to testes but also the postadolescent differences in beards, pitch of voice, and breast development.”

All male and female mammals have mammary glands, which is the organ that produces milk. When mammary glands mature fully in females during puberty, they develop into a state where a hormonal spike—most notably of prolactin—can easily induce lactation. For males, the gland generally doesn’t mature to that level.

So the difference is a matter of hormonal influence, first during puberty and then again after pregnancy. Men do have the necessary equipment, but usually they don’t naturally produce the necessary levels of hormones to use it. Provide the right hormones, though, and male lactation is absolutely possible.

One way to do this is through medical intervention. There are a number of ways this can be done, but generally, you need to introduce both estrogen and prolactin into the system, often by injection. Some drugs, like Thorazine—an antipsychotic popular in the mid-20th century—and the heart medication digoxin have induced milk from men as a side effect.

But how can men develop milk naturally?

The circumstances, as you might guess, are rare. One way to induce lactation from men is via starvation. During World War II, thousands of men reported lactation while held as prisoners either in Japanese POW camps or Nazi concentration camps. When a person is malnourished, the hormone-producing glands—like the pituitary gland, which generates prolactin—are impeded, but so too is the hormone-destroying liver. If proper nourishment is later provided, the glands recover much more quickly than the liver, causing hormone levels to skyrocket.

It’s also possible that something could target the pituitary gland and cause it to produce more prolactin. As breast-feeding expert Jack Newman notes, a tumor on the pituitary gland could have this effect.

There’s also a camp within the scientific community that thinks men can lactate merely through nipple stimulation. In 1978, medical anthropologist Dana Raphael claimed as much in her book The Tender Gift: Breastfeeding. Medical College of Georgia endocrinologist Robert Greenblatt later agreed with Raphael. Diamond, too, thinks this is possible.

“Mere repeated mechanical stimulation of the nipples suffices in some cases, since mechanical stimulation is a natural way of releasing hormones,” Diamond wrote. “For instance, sexually mature but virgin female marsupials can regularly be stimulated to lactate just by placing another mother’s young on their teats.”

Diamond provided several cases “in which [not pregnant] women succeeded in nursing an infant by repeatedly placing it at the breast.” Most adoptive mothers, for instance, begin lactating within three or four weeks of adoption, suggesting mere stimulation can induce enough hormonal action to produce milk. The same has reportedly happened to men, including a 38-year-old man in Sri Lanka who, in 2002, nursed his two daughters through infancy after his wife died during childbirth, according to an Agence France-Presse report.

So is it possible for men to lactate? Yes, it is. Does it happen often? Not at all. Could it happen more? Absolutely, if men decide they want the job.

“Soon, some combination of manual nipple stimulation and hormone injections may develop the confident expectant father’s latent potential to make milk,” Diamond said. “While I missed the boat myself, it wouldn’t surprise me if some of my younger male colleagues, and surely men of my sons’ generation, exploit their opportunity to nurse children.

“The remaining obstacle will then no longer be physiological but psychological: Will all you guys be able to get over your hang-up that breast-feeding is a woman’s job?”

Big Questions
What is Mercury in Retrograde, and Why Do We Blame Things On It?

Crashed computers, missed flights, tensions in your workplace—a person who subscribes to astrology would tell you to expect all this chaos and more when Mercury starts retrograding for the first time this year on Friday, March 23. But according to an astronomer, this common celestial phenomenon is no reason to stay cooped up at home for weeks at a time.

"We don't know of any physical mechanism that would cause things like power outages or personality changes in people," Dr. Mark Hammergren, an astronomer at Chicago's Adler Planetarium, tells Mental Floss. So if Mercury doesn’t throw business dealings and relationships out of whack when it appears to change direction in the sky, why are so many people convinced that it does?


Mercury retrograde—as it's technically called—was being written about in astrology circles as far back as the mid-18th century. The event was noted in British agricultural almanacs of the time, which farmers would read to sync their planting schedules to the patterns of the stars. During the spiritualism craze of the Victorian era, interest in astrology boomed, with many believing that the stars affected the Earth in a variety of (often inconvenient) ways. Late 19th-century publications like The Astrologer’s Magazine and The Science of the Stars connected Mercury retrograde with heavy rainfall. Characterizations of the happening as an "ill omen" also appeared in a handful of articles during that period, but its association with outright disaster wasn’t as prevalent then as it is today.

While other spiritualist hobbies like séances and crystal gazing gradually faded, astrology grew even more popular. By the 1970s, horoscopes were a newspaper mainstay and Mercury retrograde was a recurring player. Because the Roman god Mercury was said to govern travel, commerce, financial wealth, and communication, in astrological circles, Mercury the planet became linked to those matters as well.

"Don’t start anything when Mercury is retrograde," an April 1979 issue of The Baltimore Sun instructed its readers. "A large communications organization notes that magnetic storms, disrupting messages, are prolonged when Mercury appears to be going backwards. Mercury, of course, is the planet associated with communication." The power attributed to the event has become so overblown that today it's blamed for everything from digestive problems to broken washing machines.


Though hysteria around Mercury retrograde is stronger than ever, there's still zero evidence that it's something we should worry about. Even the flimsiest explanations, like the idea that the gravitational pull from Mercury influences the water in our bodies in the same way that the moon controls the tides, are easily deflated by science. "A car 20 feet away from you will exert a stronger pull of gravity than the planet Mercury does," Dr. Hammergren says.

To understand how little Mercury retrograde impacts life on Earth, it helps to learn the physical process behind the phenomenon. When the planet nearest to the Sun is retrograde, it appears to move "backwards" (east to west rather than west to east) across the sky. This apparent reversal in Mercury's orbit is actually just an illusion to the people viewing it from Earth. Picture Mercury and Earth circling the Sun like cars on a racetrack. A year on Mercury is shorter than a year on Earth (88 Earth days compared to 365), which means Mercury experiences four years in the time it takes us to finish one solar loop.

When the planets are next to one another on the same side of the Sun, Mercury looks like it's moving east to those of us on Earth. But when Mercury overtakes Earth and continues its orbit, its straight trajectory seems to change course. According to Dr. Hammergren, it's just a trick of perspective. "Same thing if you were passing a car on a highway, maybe going a little bit faster than they are," he says. "They're not really going backwards, they just appear to be going backwards relative to your motion."

Embedded from GIFY

Earth's orbit isn't identical to that of any other planet in the solar system, which means that all the planets appear to move backwards at varying points in time. Planets farther from the Sun than Earth have even more noticeable retrograde patterns because they're visible at night. But thanks to astrology, it's Mercury's retrograde motion that incites dread every few months.

Dr. Hammergren blames the superstition attached to Mercury, and astrology as a whole, on confirmation bias: "[Believers] will say, 'Aha! See, there's a shake-up in my workplace because Mercury's retrograde.'" He urges people to review the past year and see if the periods of their lives when Mercury was retrograde were especially catastrophic. They'll likely find that misinterpreted messages and technical problems are fairly common throughout the year. But as Dr. Hammergren says, when things go wrong and Mercury isn't retrograde, "we don't get that hashtag. It's called Monday."

This story originally ran in 2017.

Big Questions
What Is Fair Trade?

What is fair trade?

Shannon Fisher:

Fair trade is a system of manufacturing and purchasing intended to:

1) level the economic playing field for underdeveloped nations; and

2) protect against human rights abuses in the Global South.

Fair trade farmers are guaranteed fair market prices for their crops, and farm workers are guaranteed a living wage, which means workers who farm fair trade products and ingredients are guaranteed to earn enough to support their families and comfortably live in their communities. There are rules against inhumane work practices. Fair trade farming organizations are monitored for a safe work environment, lack of discrimination, the freedom to organize, and strict adherence to child labor laws. Agrochemicals and GMOs are also forbidden. If these rules are not followed, a product will not receive fair trade certification.

The quality of life in many communities producing fair trade-certified goods is greatly improved. Sometimes, farming communities are given profit sharing from the companies that source their ingredients, and those profits go to improving the community as a whole—be it with a library, medical facilities, town infrastructure, or opening small businesses to support the residents. A major goal of fair trade is to help foster sustainable development around the globe. By helping farming communities in third-world countries, the economy of the entire region gets a boost.

This post originally appeared on Quora. Click here to view.


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