Trends in heterosexual inexperience among young adults in Japan: analysis of national surveys, 1987-2015.

The proportion of young Japanese adults with no experience of heterosexual intercourse had increased in the past two decades. Among adults in their thirties, around one in ten had no heterosexual experience. Unemployment, temporary/part-time employment and low income were associated with heterosexual inexperience among men. Further research is needed on the factors contributing to and the potential public health and demographic implications of the high proportion of the Japanese population that remains sexually inexperienced well into adult age.