On Not Hurting Your Kids' Balls

"These days, the newer the baby, the more likely we are to carry it. (For good reason.) But the ancient Greek physician Soranus thought that babies, especially boys, should not be carrieduntil four months of age. Carrying posed the risk of severe testicular injury, Soranus thought. Today we worry about raising children who aren’t well-adjusted; the Greeks worried about raising children who weren’t eunuchs. This bias against carrying held through medieval times, apparently."

from Slate