Ghaznavi C, et al. - Using data from the National Fertility Survey of Japan (1987–2015), researchers analyzed trends in heterosexual inexperience (no experience of sexual intercourse with someone of the opposite sex) among adults aged 18–39 years. They assessed the age-adjusted prevalence of heterosexual inexperience for each survey year, sex, and age group. In the past two decades, an increase in the proportion of young Japanese adults with no experience of heterosexual intercourse has been reported. Having no heterosexual experience was reported by ~10% of adults in their 30s. Factors related to heterosexual inexperience among men were unemployment, temporary/part-time employment, and low income.