To say our society is obsessed with breasts is an understatement—after all 300,000 women go under the knife for breast augmentation every year in the U.S. alone. This video from our friends at asapSCIENCE does attempts to answer all of your burning questions about boobs. Turns out, for half of women, one breast is bigger than the other—most of the time it’s the left one. Perhaps most fascinating is how our bodies produce breast milk. Sometimes all it takes is a baby crying—and it doesn’t have to be your own—to trigger production.