As seen online:
“If natural selection had strongly disfavored left-handedness, it would have been eliminated long ago, but it hasn’t been. Left-handers make up roughly 10% of every human population ever studied, and cave paintings and skeletal evidence confirm this proportion has remained stable for millennia. The most compelling evolutionary explanation is frequency-dependent selection: being left-handed confers an advantage in competitive face-to-face interactions (e.g., combat, wrestling, certain sports, etc.) precisely because most opponents have trained against right-handers. The minority is maintained because it is rare enough to be surprising.”
— from Why Are 90% Of Humans Right-Handed? An Evolutionary Biologist Explains as of 20 June 2026