About 40 percent of those aged between 17 and 19 think sex education at school is useless, an online survey by a Japanese think tank showed Thursday.Almost one in four respondents said they have experience with sex and three out of four people surveyed said they are worried about sexually transmitted diseases. Nearly 90 percent feel that contraception is necessary, according to the Nippon Foundation.In the survey conducted in October targeting 800 young people across Japan, 59.1 percent said sex education at school was useful while the remainder said it was of no help.A female respondent sa…READ FULL ARTICLE