Evolutionary theory predicts that females will observe and rank the features of potential sexual partners, and use these to make the best possible mating choices. In humans, infant care is unusually burdensome, and many studies have shown that a female has enhanced reproductive success if she can recruit the help of a committed and attentive male partner. Thus, if any particular male feature predicted this future male behavior, women who recognized it and ranked it highly would leave the most offspring and come to dominate the population.
This study is designed to determine if testicle size is such a predictive feature. Respondents should be heterosexual women who have had at least 2 sexual partners to enable comparisons. All responses to this survey will be kept confidential, and no attempt will be made to ascertain respondents’ identity. All questions must be answered in order to submit the survey. An optional e-mail address may be completed if the respondent wishes to receive a summary of the survey results. No other use of any kind will be made of this e-mail address.