Weird Science from Japan

Is there something strange in the water? According to this article from The Telegraph (U.K.), over a third of young Japanese men are not interested in sex. That's fellows aged 16 to 19, an age when healthy young men should be interested in little else. The article also says forty percent of married Japanese are avoiding sex.

This survey data comes from the Japanese Ministry of Health, Labor and Welfare. I wonder if there is something in the Japanese culture that says you don't admit an interest in sex to the government?