In a study published Monday by the journal Pediatrics, unpasteurized human breast milk purchased online was found to contain harmful bacteria. What kind of bacteria exactly?


Of the 101 human milk samples collected for the study, 63 percent tested positive for staphylococcus, 36 percent contained streptococcus, and 3 percent had traces of salmonella. Sarah Keim, an assistant professor at Nationwide Children’s Hospital in Columbus, Ohio, and the lead author of the study, suspects that poor personal hygiene on the part of the sellers was likely responsible for much of the contamination. “Maybe they weren’t washing their hands before collecting the milk, or they did it after changing diapers or using the restroom,” she speculates. “That’s how bacteria usually found in human or animal waste gets into milk.”

Wait, people really buy breast milk on the Internet? Is this common?

When Keim was preparing her study in 2011, she found at least 13,000 “unique postings” on various websites requesting or offering breast milk for sale. While there are no firm statistics, “at least anecdotally it’s quite common,” says Kim Updegrove, president of the Human Milk Banking Association of North America. “It appears that on any given day, there are several thousand offers being made online for human milk.”

How much does breast milk cost?

It depends on the source. The sellers Keim contacted charged between 50¢ and $3 per ounce. “The average was right around $1.50,” she says. Milk banks, which promise a more vigorous screening process for their donors, can charge up to $6 an ounce. It may not sound like big money, but it can add up. During the first six months of an infant’s life, the average intake is around 25 ounces a day.

The study says that samples were purchased from a “popular U.S. milk-sharing Web site.” Why wasn’t the site named?

Keim says they’re “not really out to target one website or another.” Some news sources, however, have linked the study to In what may be a coincidence, the website went offline on Monday just as the findings became public. Glenn Snow, founder of the website, said in a statement that the company has “made the decision to transition away from offering breast milk classified ads and in the near future completely remove them with the goal [of stopping] all…activities related to informal milk sharing.”

The fallout could be far greater than just the fate of one website. Emma Kwansica, a breastfeeding advocate who founded Human Milk for Human Babies, an international milk-sharing site with Facebook pages devoted to every U.S. state, worries that the study will be used “to demonize the whole process of community milk sharing.” Purchasing breast milk online from a stranger is, she says, a very different thing from peer-to-peer milk sharing. “With local milk sharing, you’re meeting people face to face,” Kwansica says. “It’s a whole other level of security and screening.” She also wonders why, if the Pediatrics study is accurate, there hasn’t been a rise in infections and diseases among infants. “If babies were getting sick from this, trust me, I’d be the first to know,” she says. “But they’re not.”

Do advocates doubt the data in the study?

For her part, Kwansica believes the evidence is sound but questions whether the milk purchased for the study was intended for infants. As Keim admits, her research team avoided sellers who asked too many questions. “We needed complete anonymity for the integrity of our research.” But Kwansica suspects this is exactly why they ended up with tainted samples. “I know many women who have tried to sell on that exact website,” she says of, “and unfortunately it’s quite common that many of the people willing to purchase human milk anonymously are almost always men.”

Say what?

“The women selling their milk are smart,” Kwansica says, “and they know that if someone requests a small, one-time quantity of milk”—as Keim and her fellow researchers did —”it’s not going to a baby in need. They were probably like, ‘This is just going to some seedy dude.’ Why would they be concerned with washing their hands or keeping everything hygienic and clean? There’s a whole customer base of breast milk fetishists out there who…”

Thank you, that’s more than enough information.

Are you sure? Because it’s a fascinating subculture of…

Nope. Thank you, let’s move on. For parents with a legitimate need for human breast milk for their infants, what are the options?

Most milk banks across the country follow strict guidelines set by the Human Milk Banking Association of North America, providing pasteurized milk from screened donors. But that milk is only available to premature or health-risk infants. You can take your chances and buy milk from a stranger online, but as Updegrove says, “you’re making some very big assumptions about [the donor’s] health, about her ability to express and store and transport that milk in a safe way.” If you get a supply contaminated with salmonella, there’s no legal defense. “There’s no regulation of informal sharing of milk,” Updegrove says. “You shared a body fluid. You’re on your own.”

Even if you use a nonprofit “milksharing network” where no money changes hands, such as Human Milk for Human Babies, you need to do your homework. Lindsey Ward, a mother of two from Woodbridge, Va., used the service in 2010 and “made sure to ask questions about the mother and her home. I asked about her diet, any illnesses or diseases, if she knew proper handling and storage of breast milk. I saw their babies and saw them thriving and healthy from the same milk that I was receiving.”

In other words, never pay for breast milk?

Kwansica says she doesn’t have a problem with women selling their breast milk for money. But, she adds, “there is a huge risk increase when you involve the profit model. You lose that altruism and the intentions are more suspect. If somebody is selling their milk because they need the money, how far are they willing to go? There’s more incentive to lie when money is changing hands.”

Lie about what?

Keim’s research hasn’t ended with the findings published in Pediatrics. “When money is part of the equation,” she says, “it increases the incentives to perhaps boost the volume of what you’re selling. Or provide something that’s easier to obtain than breast milk. It’s always a lingering possibility.” Keim has decided to take a closer look at the samples from her initial study “just to make sure it’s 100% human milk. Because you never know.”

(This story originally appeared, in a slightly different form, in Bloomberg Businessweek.)