What’s the point of oral sex?

A new study in scientific journal Evolutionary Psychology has attempted to delve into the scientific and evolutionary reasons why men perform oral sex on women.

By polling 243 adult men in heterosexual relationships, researchers at Oakland University in Rochester, Michigan, determined that men perform cunnilingus as part of a “mate-retention tactic” to minimise the risk of their partners’ infidelity. 

Reactions to the study have been mixed, however, with many readers criticising the scientists for looking at all human behaviour as “mechanic”, and for failing to ask why women perform oral sex on men, which, in scientific terms, is seemingly just as much of a mystery. 

In their study, called “Is cunnilingus-assisted orgasm a male mate-retention strategy?”, the researchers hypothesised that one reason men perform oral sex on women is to increase her satisfaction with the relationship, and therefore minimise the risk of infidelity. 

Another possible reason for cunnilingus is sperm retention; the study notes that previous research has found that women retain more sperm when they orgasm soon after their partner’s ejaculation. 

They apparently retain more sperm in this way because a female orgasm has been shown to cause uterine contractions, “which pull sperm further into the reproductive tract”. 

According to the study, this could be why performing oral sex on women is evolutionarily beneficial, since the retention of sperm promotes conception. 

Participants in the study were asked about their most recent sexual encounter with their partner, whether he performed oral sex on her, and whether she experienced an orgasm as a result. 

The researchers found that the theory that cunnilingus was a sperm-retention tactic was not consistent with the results. 

This was because “ejaculation usually does not occur in the brief time period during which orgasm might function to retain sperm”. 

This “brief time period”, according to the study, is one minute before and up to 45 minutes after the man ejaculates into his partner’s vagina. 

The research was, however, consistent with the theory that cunnilingus was used as a mate-retention strategy. 

“Men at greater recurrent risk of sperm competition are more likely to perform cunnilingus on their partner until she achieves orgasm,” the study states. 

They concluded that “cunnilingus and female orgasm may be best explained as elements of a broader male mate-retention strategy, but also that a single hypothesis alonemay not provide a complete explanation”. 

Some readers have criticised the study altogether, deeming it “pointless” and asserting that not all human behaviour needs to have a scientific reason behind it. 

“We have not just had sex for the purpose of babies for a long, long time,” one commenter stated on TheGloss.com, adding as an example: “Prostitution is as old a profession as agriculture. 

“They may as well question why we can all sit civilly in a restaurant instead of scratching and snarling at anyone who seems to have more or better food than us or our direct offspring.” 

Others have questioned why the study places such an emphasis on the “mystery” of the female orgasm, saying: “It’s no more mysterious than why we perform oral sex on men.” 

One commenter took a more humorous approach to the research: “If you have to ask that question, then you aren’t doing it right,” he wrote. 

And another said simply: “I think hedonism explains it pretty well, but it is nice someone will try to enlighten us all.