Japan's sex problem is setting up a 'demographic time bomb' - and it could be spreading

Japan has a sex problem, and it might be contagious.

For 25 years, the country has seen falling fertility rates coincide with widespread aging, a worrisome trend that has now reached a critical mass known as a "demographic time bomb."

Japanese women are having so few children that the country's population could drop by half in 24 years.

The data reveal that roughly a million babies were born in Japan in 2015. Meanwhile, 1.3 million people died. That's a net loss of almost 300,000 humans.

New data released by UBS makes the trend especially concerning. Not only is Japan's population dwindling, but other countries might be only a couple decades behind if they can't keep their fertility rates in step with aging populations.

"There has been scarcely any nominal GDP growth over the past 20 years in the Japanese economy," UBS wrote in its report. "Demographic changes can be blamed for triggering this, and many developed and developing nations could follow the same demographic pattern as Japan's from the 1990s."

Economists refer to the trend as the "Japanization" of the global economy.

As UBS finds, many of the factors underlying Japan's ongoing fertility problem could crop up in other countries that fall below a critical threshold. Sociologists refer to that threshold as "replacement fertility," or the number of kids a woman needs to have for the population to hold steady. Generally, it's determined to be 2.2 children per woman.

Combined with aging populations, countries below replacement fertility could have the same kind of working-age population declines in the coming decade that Japan is dealing with now.

Some of those countries include USA, Denmark, China, and Singapore (fertility rates: 1.87, 1.73, 1.6, and 0.81, respectively), though Japan's case may be the most severe.

Fertility rates often fall because of changing social attitudes. In Japan, for example, a growing number of men are losing interest in sex. Because of their disinterest in physical intimacy, or "flesh," as one Japanese writer noted, these guys are known as "herbivore men."

Changing attitudes around women's roles also factor into the trend. Like many women in industrialized societies, Japanese women are delaying marriage or foregoing it altogether. In the event women do want to start a family, poor work-life policy make it nearly impossible to raise a family and keep a steady career. Over the last couple decades, women have started simply choosing work over family.

Combine that with the country's enormous elderly population, and a time bomb begins to seem more like an inevitability. But as UBS notes, that doesn't have to be the case.

If Japan and other countries want to boost their economic output (and save themselves from irrelevance), they need to make it easier for people to start families while also contributing to the demands of their jobs, the research suggests.

That could look like a greater investment in parental leave policies or flexible labor structures, where new parents can either take big chunks of time or come and go as they please - or some combination of both.

If countries want to avoid even a taste of the decline Japan is experiencing, they'll need to re-evaluate how to give people the means to live life the way they see fit.