It is unsurprising that the Internet, a place that allows commerce of pretty much every variety, would give birth to a phenomenon known as a "milk exchange." Since around 2005, sites like Only The Breast and Milk Share have acted as craigslists, of sorts, for human milk, sharing listings from both parents looking to sell excess breast milk and those looking to buy it. Exchanges like these are possible not only because of the communicative ease of the web, but also because breast milk is largely unregulated, especially compared to other body fluids like blood and semen. "Is it a food? Is it a body fluid? Is it a drug?" the Center for Biobehavioral Healths' Sarah Keim told The Verge. "The FDA really doesn't know what to do with breast milk."