Women are overcome with guilt when it comes to the organ grinding rituals known as one night stands, while men are simply riddled with an overwhelming regret that they didn’t bone enough chicks in their life.

According to a study from the University of Texas and the University of California, this type of regret is essential for the survival of the species and plays a large role in evolution.

"For men throughout evolutionary history, every missed opportunity to have sex with a new partner is potentially a missed reproduce opportunity - a costly loss from an evolutionary perspective," said UCLA social psychology professor and researcher Martie Haselton.

Men essentially regret three things: not being aggressive enough in their pursuit of a potential partner, not sleeping with more girls when they were younger, and not sleeping with more women when they were single.

However, the regrets of women are vastly different, including the loss of their virginity to a less than desirable partner, cheating on boyfriends and husbands, and having drunken one night stands.

"The consequences of casual sex were so much higher for women than for men, and this is likely to have shaped emotional reactions to sexual liaisons even today," said Haselton.

Interestingly, researchers found that the biggest regret for women was “having sex with a physically unattractive partner,” while men did not seem to care much about that minute detail at all.

The report was published in the Archives of Sexual Behavior