Back in June 2011, British prime minister David Cameron backed proposals tackling the sexualisation of British children, in a bid to dilute the culture of sex that has swept western nations. The rhetoric goes that the ‘oversexualisation’ of society, as represented in everything from ‘lads mags’ to advertising boards promoting shampoo, has fuelled a surplus of sexual desire that is thought to have contributed to the rise of teenage pregnancy and rape cases in the UK.

Compare this to Japan, a country where, according to a recent survey, a third of young men have no interest in sex. Moreover, 50% of young women are not dating. Could this be an ‘undersexualised’ society? Has this impacted Japan's population geography?

In 2007, Japans population reached a tipping point. It was the first year in its history (excluding 1945) where the number of deaths exceeded the number of births. In 2007 there were 2,000 more deaths than births. In 2011 that figure rose to approximately 204,000, and it's a figure that is accelerating. Indeed, at 23.1%, Japan has the highest proportion of over-65s in the world, and at 13.2%, the world's lowest proportion of under 14s. Japan's population peaked at 127.7 million in 2007, and is forecast to shrink to a mere 47 million by 2100. What are the economic and social forces behind this?

Too much work, too little sex: Japan is a country where sales of adult diapers exceed child diapers, and where more public money is spent on healthcare than defence. It's also one of the world's most industrialised countries, with an agricultural sector comprising 1.5% of its GDP and services sector comprising 75.7% of GDP. For Japanese society, this means that a white collar lifestyle predominates. High salaries with high workloads in an already expensive country has meant that starting a family has become a low priority, if a priority at all, on a Japanese professional’s wish list. The little available data on the reasons why indicates that raising a child is too expensive, and that the pressure of work leaves little time available to look after anyone other than themselves.

Compounding this battle between a high flying job versus a family is a culture somewhat void of sexualisation. It is unlikely that, on a stroll through Tokyo, you will come across much imagery that is overtly sexual. In contrast with the west, sex doesn’t sell in Japan. Among males 16 to 19 year old, 36% have no interest in sex, and some even despise it. The figure is even higher (59%) for females in the same age category. These respondents often cite greater interest in comics, computer games and socialising through the internet. A low level of cultural sexualisation is not without its benefits; the rape rate is one of the lowest in the world.

However, the net result of these socio-cultural and economic factors is that the fertility rate is astonishingly low. According to the UN the figure is 1.27.

Japan is therefore facing a demographic crisis. The number of dependents per active member of the labour force is increasing, and in an unusual situation, there are more jobs available than people to do them. Furthermore, in future decades Japan may have an oversupply of infrastructure relative to the amount of people who can use it.

Several policy options could be under consideration by Japan's decision makers. Not all of these are practical or even advisable, but we may see them looked at in years ahead:

Encourage Fertility – This would help ensure that the labour market and services such as transport are not undersupplied. It can be done in at least three ways. The first is through pro-natal incentives, such as child tax breaks for couples who desire children. The second is to restrict or even ban abortion (Japanese abortion laws are some of the most liberal in the world). For example, restrict abortions to the first trimester only. Laws such as these will inevitably conflict with women's and couples rights. The third, and perhaps the most untried, is to sow the seeds for a more sexualised Japanese culture, one with more lust and desire, in an attempt to situate relationships as more desirable than the latest computer game.

Encourage Migraton – Japanese immigration and emigration have both been low. The ethnic mix of Japan is not diverse. 98.5% of Japan's population is ethnically Japanese, with only a few other ethnic groups. In order to prevent an undersupply of labour, the country may have to encourage mass immigration. Given the unique culture and language of Japan, will foreigners want to come and live there? Would immigration cause ethnic tensions in this peaceful country?

Raise the Retirement Age – It has been calculated by United Nations researchers that the retirement age in Japan would have to be raised to 77 from 65 in order to rebalance its crippling dependency ratio. This would shorten the average amount of retirement years from 14 years to two for men, and from 19 years to seven for woman.

A blueprint for the rest of the world? Is Japan's pattern of rising, peaking, and falling gross population going to be a defining demographic trend in the 21st century? In Japan, Germany, Russia, Czech Republic, Estonia and several more countries it already is, with several other low growth European countries, such as Italy, forecast to head the same way.

Low sexualisation is unlikely to be an important factor of low growth in Europe. The worldwide trends of continued urbanisation, the growth of white collar jobs, and the decline of blue collar jobs as an overall percentage of the economic makeup have acted as the most effective mass contraception.

Given a course of continued social and economic development around the world, the ‘tipping point’ for world population could be as near as 2050, a date that many of the readers of this article could be witnessing.

The rhetoric of overpopulation doomsday scenarios should really be reversed. The warnings today should be about the unsustainable dangers of a shrinking population. This will no doubt be one of the key issues in sustainable development discourse for years to come.

Edward Morgan is a 4th Year Human Geography student at the University of St Andrews, Scotland.

Photo by Kevin Poh: Night Life @ Shinjuku, Tokyo