Julian Ryall, Telegraph, January 20, 2015

Nearly 50 per cent of all Japanese adults are not having sex, according to a study, dealing a new blow to government efforts to halt the sliding birth rate.

The report, conducted by the Japan Family Planning Association, determined that 49.3 per cent of the 3,000 people interviewed had not had sex in the previous month.

Of the men interviewed, 48.3 said they had not had sex for a month, while 50.1 per cent of women had abstained. Both figures were up about 5 percentage points from the previous study, conducted in 2012.

Asked why they were not having sex, 21.3 per cent of the married men claimed they were too fatigued after work while 15.7 per cent replied that they were no longer interested in sex after their wives gave birth.

Among the women, 23.8 per cent said sex was “bothersome” and 17.8 blamed being tired from work.

Another worrying statistic was the increasing number of young men with little or no interest in sex, a group known as “herbivores” in Japan.

More than 20 per cent of men aged between 25 and 29 expressed little of in interest in sex.

The population of Japan currently stands at 126.6 million, although 25 per cent of that total are aged 65 or older, an increase of 1.12 million people on the fiscal 2012 figure. Equally, the fertility rate of 1.41 babies per woman during her lifetime means there are not enough babies being born to sustain the population at its present levels.

If those trends continue, the National Institute of Population and Social Security Research has warned that there will be a mere 49.59 million Japanese by 2100, a decline of more than 61 per cent on the 2010 figure.

The government has attempted a series of campaigns to encourage couples to have more children–from making companies insist that their staff leave work at 6pm to increasing child allowances–but none of that is gong to have an impact if people are not going to have sex, the authors of the report point out.

In a similar survey conducted in Britain, more than 60 per cent of adults said they had had sex within the past four weeks.