There's no evidence of any trend that young people in Japan have stopped having sex. That is what I was trying to point out: not being in an old-fashioned relationship, and not actually bearing children, does not any longer have any kind of direct relationship to how much sex you are having.
There may well be ongoing generational changes to reproductive and marriage/relationship behavior in Japan, as there is elsewhere (c.f. everywhere on Earth), but this article doesn't go there.
I look toward the prospects of women in Japan for an indication as to what's wrong. These are people who have grown up with dreams that society seems unwilling to support. For how many women in Japan is 'Maybe it's time to have a kid in the next few years' tantamount to "I must give up any dreams of having a career"?
And why not just more one night stands? Because they are short on commitment (feel alone and, thus, scared in the morning), caring, ..., children.
And just for passion, a good version requires the couple to have had a lot of time together and to care about each other -- e.g., for a man, the best result of passion is that, net, she smiles the rest of the evening, the next morning, and well into the next day, and that takes some mutual caring, practice, and effort.
Why so value the smiles? Because they promise 1000 more good evenings of passion instead of maybe 0, lots of good back rubs, a nice breakfast, lots of 'contact comfort' for, say, another 24 hours, etc.
This doesn't fit the article:
> A survey earlier this year by the Japan Family Planning Association (JFPA) found that 45% of women aged 16-24 "were not interested in or despised sexual contact". More than a quarter of men felt the same way.
So A: the person asking the questions isn't a reporter, B: they aren't British, and C: they have every reason to figure out a way to get people to answer the questions honestly, i.e., not "cultural misunderstanding" where someone at a party lies about how much sex they have.
What your argument really boils down to is: "no measurement, real or otherwise, could ever possibly indicate that Japanese people are having less sex": i.e. your post is unfalsifiable, and your claim thusly ludicrous.
>There may well be ongoing generational changes to reproductive and marriage/relationship behavior in Japan [...] but this article doesn't go there.
Did you read it?
>Japan's Institute of Population and Social Security reports an astonishing 90% of young women believe that staying single is "preferable to what they imagine marriage to be like".
So we can correctly interpret your post: what precisely is "going there", if not this?
The article is also based on the opinions of two people who have been claiming to study Japanese sexual behavior: the therapist Ai Aoyama and the sociologist Nicholas Eberstadt. Certainly the opinion of two "experts" is not a conclusive analysis of a situation, but this is a pretty ordinary way of sourcing information for a news article. It isn't particularly "stupid" for this. Which is why statements like this:
>There's no evidence of any trend that young people in Japan have stopped having sex.
make you look dishonest in light of this:
http://www.ipss.go.jp/site-ad/index_english/nfs14/Nfs14_Sing...
http://www.durex.com/en-jp/sexualwellbeingsurvey/documents/g...
http://search.japantimes.co.jp/cgi-bin/fl20110906ad.html
You can dispute the strength of the evidence, but it isn't "no evidence".