Findings of a new research study have revealed that men and women either fall into two categories. They are either more inclined to be promiscuous or faithful when it comes to sex.
For the new study published in the journal Biology Letters on Feb. 4, University of Oxford experimental psychologist Rafael Wlodarski and colleagues used an online questionnaire that evaluated a person's attitudes and desires toward noncommittal sex. It was completed by 575 respondents from North America and the U.K. who were almost 25 years old on average.
The researchers also measured the length of the index and ring finger of 1,314 British men and women using photocopies of their right hand for an investigation based on what is known as the 2D:4D ratio.
The premise of the 2D:4D is that the length of a person's ring finger indicates the level of testosterone he or she was exposed to in the womb. A person with shorter index finger compared with the ring finger had higher levels of testosterone while developing in the womb.
Earlier studies suggest that exposure to higher levels of fetal testosterone is associated with greater sexual promiscuity in adulthood. Although the ratio of the length of the ring and index fingers is not predictive of individual behavior, this helps identify individuals who have the tendency to be promiscuous.
The datasets revealed that 57 percent of the male subjects had increased odds of being promiscuous and 43 percent were more likely to be faithful. Forty-seven percent of the women, on the other hand, were more likely to "stray" and 53 percent fell within the "stay" category. As for the 2D:4D study, the researchers found that 62 percent of men and 50 percent of women fell within the stray category.
"Our results suggest that the proportional split in males slightly favours an unrestricted (short-term) mating strategy, with a 57 : 43 split on average for the three datasets, whereas females have a reversed split (47 : 53)," Wlodarski and colleagues wrote. "However, the mixing proportions in the 2D : 4D digit ratio dataset suggest that a slightly higher proportion of the unrestricted phenotype is present in both sexes (males approx. 62 percent, females approx. 50 percent)." Phenotypes are a list of physical characteristics -- for example, height, eye color and and blood type, observable traits that result from interactions between a person's genes and the environment.
The researchers warned that there is a need for caution when interpreting the results of their study.
"Human behavior is influenced by many factors, such as the environment and life experience," said study author Robin Dunbar, from the University of Oxford.
