Ever noticed how some families seem to be exclusively boys or girls? No, it’s not just random luck or a quirk of genetics—it turns out, there's some fascinating science behind these all-boy or all-girl family trends. A recent NPR article titled “Have all girls or all boys? Study suggests the odds aren’t 50/50” dives into decades of birth data and reveals a surprising pattern: larger families tend to have children with the same sex more often than we’d expect by simple chance. Intrigued? You should be! This discovery shakes up everything we thought about the randomness of gender at birth.