It's a question that has puzzled scientists for decades - why do straight men love breasts? 

Now, experts from the University of Wrocław say they may have finally found the answer. 

For years, researchers have debated whether men's fixation on breasts is innate or simply the result of cultural conditioning in the West.

In their new study, they wanted to know: would men who had grown up surrounded by topless women be less interested in breasts? Or was the attraction hardwired? 

To answer these questions, the researchers studied the Dani tribe of Western New Guinea, Indonesia. 

Until about 20 years ago, it was the norm for Dani women to go topless. 

But as Western influence spread, most women began covering up. 

The team surveyed 40 older Dani men who came of age when toplessness was the norm, and 40 younger men who grew up in a society where women covered up. 

The men were asked how frequently they touch their partner's breasts, and how sexually aroused they feel when they see naked female breasts. 

The results revealed that there was no difference between the two groups.  

'The two groups did not differ in terms of how frequently they touch their partner's breasts during sexual intercourse, [or] how sexually aroused they feel when they see naked female breasts,' the study, published in Archives of Sexual Behaviour, concluded.

In other words, even in a society where breasts were freely on display, men still found them attractive. 

Despite just researching one tribe and it relying on the older men's recollections, lead researcher Michal Stefanczyk said that it seemed reasonable to assume that this was not a cultural imposition. 

Stefanczyk told the Times: 'What we can say is breasts are sexy — naturally so. 

'Men like breasts.'

However, he was keen to point out that this doesn't mean breasts are the be-all and end-all for men.

In fact, many of the Dani men said breasts weren't a major factor in choosing a life partner.

Steve Stewart-Williams, a psychology professor at the University of Nottingham Malaysia, said: 'I've often heard people argue that men's love of breasts is just an invention of Western culture, and that there are cultures out there where breasts are no big deal to men.

'It's always struck me as implausible — could Western culture have randomly created a male obsession with women's elbows or nostrils? I find the new study persuasive. 

'And it also strikes me as a win for common sense over an eccentric academic theory.'

The study comes shortly after scientists claimed to discover the formula for the perfect woman's body.

According to scientists from the University of Konstanz, the most attractive women have a pronounced 'S' shaped contour from the chest down to their thighs.

This could explain why curvier stars such as Marilyn Monroe or Kim Kardashian are often considered more attractive than slimmer celebs.

The researchers say it is a woman's overall 'curviness' which makes them appear attractive rather than just having a slim waist. 

These findings overturn older research which assumed that a waist-to-hip ratio of 0.7 was the ideal body shape for a woman.

However, the researchers say that a lower waist-to-hip ratio is only attractive for women with a lower body weight.

For larger body types, it is curviness rather than waist size which was the key factor in someone's attractiveness.