Monogamy is defined by Merriam-Webster’s dictionary as “the practice of marrying only once during a lifetime, or the state or custom of being married to one person at a time or, the condition or practice of having a single mate during a period of time,” while the definition for ‘promiscuous’ is being “not restricted to one sexual partner”.

When it comes to monogamy and promiscuity, it is often said that women prefer to be monogamous, while men prefer to be promiscuous.  University of California, Los Angeles professor of Women’s Studies, Letitia Anne Peplau, suggests that men are more concerned about sex than women, and that this is because assertiveness and dominance are more associated with male sexuality than female sexuality.

In the largest study done on human sexual behaviours, known as the International Sexuality Description Project led by David Schmitt, an evolutionary psychologist from Bradley University, researchers surveyed 16,288 people (mostly college students) from 52 countries found that men tended to seek sexual variety, while women tended to seek long-term monogamous relationships. In the study males and females women were asked how many partners they would like to have in the next month, while the average response from the males was 1.87, the average response from the females was 0.78. Males and females were also asked how many sexual partners they desired in the next ten years and while the males were found on average to want 5.95 partners, females were found to want about 2.17 partners in the next ten years. David Schmitt, suggests that men are born to be promiscuous and says that,"the results are strong and conclusive -- the sexes differ, and these differences appear to be universal."  The reason for the differences between males and females, according to Schmitt, is found in ancient hunter-gatherer societies, when promiscuous males had a better chance of passing on their genes, and females who remained monogamous had a better chance of raising their children.

 Some evolutionary psychologists have hailed Schmitt’s study as definitive, indisputable evidence that these sex differences are indeed biological. David M. Buss, an evolutionary psychologist at the University of Texas in Austin, has said, “The evidence he [Schmitt] presents is irrefutable.” 

According to some feminist researchers, the responses in Schmitt’s study may have been skewed, suggesting that males may have exaggerated their responses to appear more “virile”, while females may have understated their responses so as not to appear “loose”, or like a “slut”.   For instance, feminist researchers, Michelle Alexander and Terri Fisher, conducted a study into how females self-report their sexual behaviours and attitudes, and found that females change their responses depending on whether or not they believe they will be caught out not telling the truth. In another study, researcher Deborah Tolman interviewed high school girls and found that all the girls reported feelings of sexual desire but, that the girls expressed fear over the potential negative consequences of expressing these desires, which included losing respect and reputation, as well as limiting their educational opportunities.

Another reason why David Schmitt’s study may be skewed is due to “volunteer bias”, which means that many people, especially those that tend to be more sexually promiscuous and have sexual attitudes that are more liberal, probably did not participate. 

Not only may the Schmitt study be skewed but, it also contradicts other evolutionary research which has found that females have historically been promiscuous.  In one study on the evolution of sperm, scientists found that the reason why the testicles of males are the size they are is due to the historical infidelity of females. The study examined the semen of 12 different species of primates (including humans) and found that in the species where the female is promiscuous (such as the chimpanzee) her male counterparts have large testicles, but that in species where the female tends to stay with only one partner (such as gorillas) the male has small testicles. The researchers claim that the reason for this is that in promiscuous species the sperm must often fight those of a rival to be the one that ends up fertilizing the females’ egg, so as a way to increase the chances of paternity these male species have evolved large testicles and sperm counts for their body size.  Since human males have rather large testicles and sperm count scientists concluded that females must have been historically promiscuous.

Female promiscuity has also been considered “good for the genes”. According to certain studies females who are promiscuous have a better chance of their offspring surviving because males that are successful in sperm competition also sire healthy offspring. 

The idea of women being less promiscuous than men is considered, by some researchers, to be a “sexist double standard” which was socially constructed to permit, as well as encourage, men to be promiscuous by engaging in casual sex but did not allow the same for women. Therefore research that suggests that men and women have different sexual desires, and that men are more promiscuous then women should be reconsidered in regards to the social construction of female sexual identity, and also in how male and females respond to survey’s on their sexual desires and sexual activities, before coming to any conclusions as the findings may be due to the function of gender roles, and not due to any specific evolved adaptations.