Quoting from research conducted by Frank Sommer from the University of Hamburg, the magazine said young men aged 18 to 30 had sex 18 to 22 times a month 30 years ago. Today the figure for the same age group has fallen to between four and ten times a month.
Sommer attributed the lack of interest in sex to more daily stress which was a drain to sexual energy.
'Men often have no strength and no time to have sex,' Sommer was quoted as saying.
But other factors such as blood circulation problems, psychological reasons such as depression or problems in the relationship could play a part, Sommer said.
These factors also applied to women, Sommer said. 'I'm convinced that women are no better off but men suffer more from not having sex because it doesn't fit to their male role image'.
At the same time women were more demanding sexually and more open to speaking about why the man had no energy for sex.
However the expert concludes that 'we live in an era with a little less sexual energy'.
