Part of the problem with understanding sex in Japan is cherry-picked data. Take the 2011 survey by the National Institute of Population and Social Security Research on which sex-drought stories are often based. Its finding that 61 percent of unmarried men and 49 percent of single women between 18 and 24 of age weren’t in any kind of romantic relationship is mentioned up high. Rarely cited is this fact on Page 2 of the report: almost 90 percent of respondents intend to marry someday. And what about international comparisons? A recent Pew study found that 71 percent of unmarried Americans aren’t in committed relationships. Also, there can be big cultural and generational differences in the meaning of “single,” “dating” and “having sex.”  There are important things to be learned from the Japanese experience.  How do countries manage with large aging populations and low birth rates.  William Pesek reports.  Japan Faces Aging Population and Low Birth Rates