"Men with deeper voices tend to have more children."
A study of the Hadza people in Tanzania found higher reproductive success and more children overall among men with deeper voices compared to men with high-pitched voices. Researchers have suspected that deeper voices are more attractive to women, but they selected the Hadza because their lack of birth control methods allows for a more direct link between measurable vocal pitch and number of children. Anthropologists suggest that either increased testosterone or the perception that deeper-voiced men are better providers could explain the findings.
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