It also shows 62 percent of the women who had abortions are between 20 to 29 years old, and most are single. One of the major reasons behind is the lack of sex education. For example, over 70 percent of the callers to a pregnancy hotline in Shanghai know nothing about birth control, and only 17 percent have some ideas of sexually transmitted disease, according to a survey done by the Hospital of People's Liberation Army. Li Ying, a professor at Peking University urged a national promotion in sex education as most Chinese parents never talk about sex with their children. "Sex education needs to be strengthened, with universities and our society giving more guidance," she told the paper. So far, all the education, including the advertising of birth control pills, is targeting married couples. For example, the morning-after pill, which is for emergency contraception, has been popular among young people since 1998, but the incorrect use is a problem, said Wu Shangchun, a division director of the National Population and Family Planning Commission's technology research center.