PLoS ONE released a study by Simmons et al. from the Centre for Evolutionary Biology of the University of Western Australia . Here is the abstract :
Low Pitched Voices Are Perceived as Masculine and Attractive but Do They Predict Semen Quality in Men?
Women find masculinity in men's faces, bodies, and voices attractive, and women's preferences for men's masculine features are thought to be biological adaptations for finding a high quality mate. Fertility is an important aspect of mate quality. Here we test the phenotype-linked fertility hypothesis, which proposes that male secondary sexual characters are positively related to semen quality, allowing females to obtain direct benefits from mate choice. Specifically, we examined women's preferences for men's voice pitch, and its relationship with men's semen quality. Consistent with previous voice research, women judged lower pitched voices as more masculine and more attractive. However men with lower pitched voices did not have better semen quality. On the contrary, men whose voices were rated as more attractive tended to have lower concentrations of sperm in their ejaculate. These data are more consistent with a trade off between sperm production and male investment in competing for and attracting females, than with the phenotype-linked fertility hypothesis.
We can't get it all. Bald men are perceived by most women as less attractive, but they tend to have higher testosterone levels, and therefore probably better sperm quality too. Isn't it ironic that females are attracted to the very traits that lower sperm count ? Is that an evolutionary way to keep the balance between the various male phenotypes, or is it a natural desire of women to increase the likelihood of conceiving girls rather than boys (a lower sperm count increases the gender bias in favour of female offspring) and therefore passing two X chromosomes instead of one ? Could the X chromosome influence the way women perceive attractiveness for its own selfish purposes ? The evolutionary battle between and X and Y chromosomes is a real one.
Low Pitched Voices Are Perceived as Masculine and Attractive but Do They Predict Semen Quality in Men?
Women find masculinity in men's faces, bodies, and voices attractive, and women's preferences for men's masculine features are thought to be biological adaptations for finding a high quality mate. Fertility is an important aspect of mate quality. Here we test the phenotype-linked fertility hypothesis, which proposes that male secondary sexual characters are positively related to semen quality, allowing females to obtain direct benefits from mate choice. Specifically, we examined women's preferences for men's voice pitch, and its relationship with men's semen quality. Consistent with previous voice research, women judged lower pitched voices as more masculine and more attractive. However men with lower pitched voices did not have better semen quality. On the contrary, men whose voices were rated as more attractive tended to have lower concentrations of sperm in their ejaculate. These data are more consistent with a trade off between sperm production and male investment in competing for and attracting females, than with the phenotype-linked fertility hypothesis.
We can't get it all. Bald men are perceived by most women as less attractive, but they tend to have higher testosterone levels, and therefore probably better sperm quality too. Isn't it ironic that females are attracted to the very traits that lower sperm count ? Is that an evolutionary way to keep the balance between the various male phenotypes, or is it a natural desire of women to increase the likelihood of conceiving girls rather than boys (a lower sperm count increases the gender bias in favour of female offspring) and therefore passing two X chromosomes instead of one ? Could the X chromosome influence the way women perceive attractiveness for its own selfish purposes ? The evolutionary battle between and X and Y chromosomes is a real one.