Sex, as the old saying goes, sells.
And one study is suggesting that a major shift might be underway in the world of sex, at least for young American men.
Survey results from the National Opinion Research Center (NORC) at the University of Chicago, which have been interpreted and analysed by the the Washington Post, suggest that fewer young men in the US are having sex than in the past.
The General Social Survey, which interviews thousands of people and has been conducted since 1972, revealed that 23% of adults said they hadn’t had sex in the past year - doubling in the past 10 years - and that “a much larger than expected” number of them were men.
The survey shows that the share of men under 30 who said they hadn’t had sex in the past year has tripled since 2008 to 28% - much higher than the 8% increase among women in the same age range.
The data, obtained from face-to-face interviews, also found that more than half of US adults between the ages of 18 and 34 (51%) don’t have a long-term partner - a figure that’s risen from 33% in 2004.
So what should we make of this data and can we draw any parallels with the UK?
Professor Simon Forrest, from the Institute for Health & Society at Newcastle University, tells BBC Three that although the US study is robust and built on a big data set, the current UK research doesn't necessarily point to a similar trend over here.
"I’m not sure that we would claim to have seen the same sort of trend in the UK yet, at least according to the long-running UK NATSAL surveys which are carried out every decade or so," he says. "But we’re due another survey in 2020 so we might wonder whether the US experience is going to be reflected in the UK in the future."
The last time we had this large survey, according to the professor, a large majority of young men and women reported having sex with somebody else in the last year and there was no indication that younger people in particular were having less sex.
However, because of similar social and cultural factors in both the US and the UK, the professor says it's worth considering what might be behind the trends.
First, many young people tend to form long-term partnerships later in life, with people not settling down until their 30s. "This is something that’s definitely changed a lot in the last 50 years," Prof Forrest says.
He also says that young people remaining dependent on their families, both financially and in terms of living at home, might be a factor. "I think this clearly has an impact on the kinds of relationships young people form because that lack of independence can be quite important," he says.
Finally, he points to what he calls the 'pornographisation' of society, in which the greater access to explicit pornography online might be affecting sexual relationships. For example, young people might be concerned about the objectifaction of their bodies, about increasing negative attitudes towards women and they might even be having fewer sexual encounters because they're spending more time with pornography.
Meanwhile, Jean Twenge, a professor of psychology at San Diego State University, says video games and Netflix could also be factors.
“There are a lot more things to do at 10 o’clock at night now than there were 20 years ago,” she tells the Washington Post. “Streaming video, social media, console games, everything else.”
On social media, commenters weighed in with some of their own theories that could be behind the change.
One person thought the rise of dating apps could be responsible.
Another thought money problems and work-related stress could be to blame.
A BBC Radio 5 Live survey in 2018 questioned 2,066 UK adults about their attitudes to sex and relationships, and stress was rated as a problem in the bedroom by more people than any other factor (45%) - but, among men, half of those questioned said they were satisfied with their sex lives.
Relate therapist Ellen Brady said at the time, "We're seeing an awful lot of clients with anxiety issues - anxiety and sex just doesn't sit together at all."
And when it comes to dating apps, which have transformed the way we find long term relationships and one night stands, there appears to be a significant difference in the behaviour of men and women. Scientists from Queen Mary University of London, Sapienza University of Rome, and Royal Ottawa Health Care Group in 2016 studied the behavior of Tinder users and found that women, by and large, only swipe right for men they're seriously interested in, while men are less picky. So even though men are swiping right more freely, they're not necessarily having much success in finding too many matches.
And even if fewer young men are having sex, so what? Maybe young people, as one person suggested online, just have better things to do.