Hoppy Beers Cause Man Boobs: Report Herbalist warns about plant estrogen that gives hops its flavor By Neal Colgrass, Newser Staff Posted Jun 21, 2015 5:00 PM CDT 34 comments Comments (Shutterstock) (Newser) – Guys, this is for you: Hoppy beers contain a plant estrogen that may cause feminine attributes, including man boobs. According to author and herbalist Stephen Buhner, hops are "female flowers of the hop plant" that contain serious amounts of phytoestrogen, a plant estrogen that women have used as an herbal medicine, Fox News reports. That's why gals have taken hops to ease menopause and boost milk production, among other things, Vice notes in an article about Buhner's work. "Yes, you read that right: Hops are giving men man boobs," says Vice. Fox notes that India Pale Ale is heavy on hops, and craft brewers use 400% to 500% more hops than the typical big-name beer. But not everyone is buying the theory: "I'm inclined to think that the man boobs are more the result of the high number of calories commonly found in hoppy (high alcohol) beers," reads a comment in the Vice article. Another notes that hop content in "a 5-gallon batch of beer—let alone a single beer—is infinitesimal." As if man-boob fear isn't enough, both articles also refer to "brewer's droop," or male infertility caused by beer—which can last for a year after heavy drinkers stop guzzling, the Telegraph reported two years ago.