It turns out breast isn’t just best – it’s worth millions. Women have been informally sharing and selling breast milk for years. (And not just for babies: there’s a market for men who like to drink breast milk, too.) You can even buy breast milk on Craigslist. But now, big business has jumped on the bandwagon.

The New York Times reported last week that Prolacta Bioscience – a company that buys, pasteurizes and sells breast milk – has raised $46m from investors betting that commercialized mother’s milk is the future.

But breast milk being turned into a commodity rather than a freely shared favor has raised some hackles: what does it mean if low income women would rather pump to sell than breastfeed their own children? Are companies already targeting poor women and women of color?

No matter the ethical implications, selling breast milk is the inevitable result of telling women they’re creating “liquid gold” with every pump. So stopping the commercialization of breast milk would mean owning up to a very unpopular truth: the benefits of breastfeeding are murky at best.

Most major studies that have been done on breastfeeding conflate correlation with causation. Yes, breastfed babies are more likely to be healthy than formula-fed children – but we don’t know why that is. As professor Joan Wolf, author of Is Breast Best?, told the Guardian in 2013, “Women who choose to go through the labour of breastfeeding have made a commitment to go the extra mile for the sake of their baby’s health”.

Moms who have the time to pump for hours a day, for example, likely have more time to play and read to their children. Women whose employers provide lactation rooms and breaks are more likely to have jobs with better pay and benefits. It’s difficult to distinguish the benefits of having a more privileged or involved parent from the benefits of breastfeeding.

Even in the most recent large-scale study on breastfeeding, researchers admitted that the role mothers play in overall development could have impacted their results. (The one proven perk of breast milk is that it helps to promote gastrointestinal health – a small benefit for healthy babies, but a tremendous one for preemies who are at risk for the deadly intestinal infection, necrotizing enterocolitis.)

Despite the shaky science, we largely accept that breastfeeding isn’t just a better choice, but the only choice if you care about your kids. When New York City launched a breastfeeding initiative, for example, participating hospitals were instructed to treat formula like prescription medicine: moms who wanted formula would have to listen to a mandatory talk on the benefits of breastfeeding and give a “medical” reason for why they wanted formula. So much for my body, my choice!

It may be that business involvement will lead to some positive changes for families who do want to use breast milk but don’t have access to it. Right now, while there are strict government regulations on bodily fluid and organ donations, there are no such standards for breast milk. I’m not keen on the idea of the government getting involved in women’s breast business, but a 2013 study found that breast milk sold on websites often contained bacteria, even salmonella. So some standards on sharing might be necessary: non-profit milk banks, for example, often test and pasteurize breast milk before making it available to women and hospitals.

No matter what the future holds for breast milk, though, we can’t be surprised when a market is created for something we continue to tout as near-magical. And if we value women’s bodily autonomy we’re going to have to get comfortable with the choices she makes – whether it’s breastfeeding, formula feeding, or pumping for cash.