Maybe the women think that the men with the high-pitched voices are gay.
Researchers have found that men with deeper voices have more children -- at least among the Hadza, a group of hunter-gatherers in Tanzania.
According to background information in an article published online for the Dec. 22 edition of Biology Letters, most women in Western societies find lower-pitched male voices more attractive, judging them healthier and more masculine. Meanwhile, men find higher-pitched voices more appealing.
The evolutionary reasons for reproductive success are difficult to discover in a society that uses modern birth control methods. The Hadza use no birth control and choose their own spouses; this makes them what the researchers call a “natural fertility population” where hypotheses about human reproductive success can be tested.
Researchers collected voice recordings (the Hadza speak Swahili) and reproductive histories from 49 men and 52 women to determine if voice pitch might affect the number of children.
After controlling for age, voice pitch was a highly accurate predictor of the number of children a man fathered, and those with deeper voices fathered significantly more. The researchers estimated that voice quality alone could account for 42 percent of the variance in men’s reproductive success. The quality of women’s voices was unrelated to how many children they had.
Update: Evolutionary psychologist Gordon Gallup says the handgrip is more important:
Gallup’s new research suggests that handgrip strength in men is directly connected with reproductive fitness.
People with high grip-strength scores are usually healthier than those with weak grips. "They live longer and recover faster from injury," Gallup says. "They have reduced disability, higher bone density and greater fat-free body mass." And in a study published this year, Gallup and his son Andrew -- at the time an undergraduate psychology major -- found that males with high grip-strength scores reported being more aggressive and dominant and had more masculine body types (broader shoulders, narrower hips). They also had "increased sexual opportunities," which resulted in an increased number of sexual partners, and younger ages of first sexual encounter.