Well, this is unexpected: 'millennials' are having less sex than our parents did.

Image: It’s Complicated.

Here’s a little factoid to spruce up your next family dinner conversation: it’s very likely you’re having less sex than your parents did at your age.

Yep, despite all the hand-wringing over Gen Y’s ‘hookup culture’ and love of apps like Tinder, it seems we’re not having as many sexual partners than the youngens of the past.

Related: 9 reasons you’re finding sex painful.

We’ll give you a moment to process. Got it? Good. (Post continues after gallery.)

While we’re definitely more accepting of premarital sex than previous generations, we also tend to have slightly fewer partners, according to a study of 33,000 people published in the Archives of Sexual Behaviour.

Boomers and early Gen Xers (those born in the 1950s and 60s) had the most sex of all, averaging 11 sexual partners as adults. Even those born in the 1940s or 1970s averaged 10 partners, while millienials (born in the 1980s and 1990s) averaged eight sexual partners. We’re still doing better than our grandparents though, who slept with an average of about two partners each.

RELATED: 9 reasons you’re finding sex painful

How is that family dinner looking now?

As for the reasons behind this change, report author Jean Twenge has some suggestions.

“Although millennials are more tolerant of pre-marital sexual behaviour, they’re not taking that as license to sleep around,” she said.

She believes the decrease in the number of partners could be due to the fact that millennials are more safety-conscious than earlier generations with a greater awareness about HIV and other STIs, rather than anything to do with the morality of premarital sex.

"Millennials have never known a world where premarital sex was a taboo," she said.

According to Twenge, the change in attitude was definitely a generation-specific thing, evolving as younger, more accepting generations replaced older ones.

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For example. the study found tolerance for homosexuality has quadrupled since 1973 to 44 per cent, but still remains the minority. This could be because people who grew up when it was a taboo may still view it in the same way.

Thought you were breaking new ground with the 'hookup' culture? Turns out our parents probably did it first.

Do you think there's a big generational gap in our attitude to sex?