Apparently, if you're a guy who wants his chances of evolutionary survival to go up, you should be going down.

According to a new study published late last month in the Journal of Evolutionary Psychology, heterosexual men perform oral sex on their partners as a "mate retention" strategy — in laymen's terms, to keep the ladies coming back for more.

This, in turn, reduces the likelihood of infidelity and increases the chances that your female partner will stick around long enough to carry your baby and advance your genes into the next generation.

Oakland University in Rochester, Mich., surveyed 243 adult men in committed, heterosexual relationships regarding their sexual behaviors. Researchers sought to test the hypotheses that men perform cunnilingus to: 1) promote sperm retention, since uterine contractions during female orgasm pull sperm further into the reproductive tract and, therefore, make it more likely for a pregnancy to occur 2) promote mate retention by deterring competition from other sperm sources, since men who bring their female partners to orgasm are presumably more sexually satisfied and, thus, less likely to turn to other men for sex.

According to the research, the sperm retention theory did not hold, but mate retention appears to be a driving, evolutionary reason behind men's performance of oral sex on women. Making a woman happy through oral sex reduces the likelihood of "cuckoldry," defined here as a man's "unwitting investment of resources into offspring to whom he is genetically unrelated."

Thus, from an evolutionary perspective, cunnilingus is a tool in a man's arsenal to retain a reliable mate, i.e. make sure the chick he's investing "resources" in won't have some other dude's kid.

Unsurprisingly, there has been some major blowback (pun intended) against the study. For one, it seems pretty sexist and loaded with double-standards. As a result of its focus on cunnilingus, the study implies that there needs to be a larger scientific justification for men to perform oral sex on women. If these scientists treat the ultimate evolutionary goal as producing offspring, Samantha Escobar at The Gloss writes, "Why aren't they questioning the evolutionary advantage of oral sex for men? Isn't that purposeless, too?" Inquisitr sarcastically suggests there is no need to investigate why women perform oral sex on men, as "everyone knows women do it for diamonds."

In fairness to the scientists at Oakland University, while their study concluded that "cunnilingus and female orgasm may be best explained as elements of a broader male mate retention strategy," they also noted "a single hypothesis alone may not provide a complete explanation." Yet, as Inquisitr points out, "suggesting that the sole purpose is to bribe a woman into fidelity" implies that making your partner feel good or happy cannot be reason enough, at least for a heterosexual man.

Others take issue with the study because it operates from the view that all individuals' ultimate sexual goal is to produce children. Not only does this study take an exclusively hetero-normative approach to sexual relations (no small flaw), it argues that "we're all just sexual Calvinists, yoked to our compulsive need to find, secure, and nurture a baby-creating union," writes Doug Barry at Jezebel. Cunnilingus is just "an old Jedi mind trick" on women to "increase relationship satisfaction, which would in turn 'encourage subsequent copulations.' Ipso facto, MORE BABIES."

Does there need to be an evolutionary justification for our 21st century sexual behavior, or for that matter, any reason other than that it makes us or our partners feel good? As one commentator at Discovery Magazine writes, "If you have to ask that question then you aren't doing it right."