City news reported that among the men who came to us for pre-childbirth checkups, 1 in 3 had poor sperm quality. Dr. Xia Xinyi from the Department of Urology at Nanjing General Hospital of Nanjing Military Region told reporters that in the last 20 years, the sperm density of men around the world has decreased by another 51 million per milliliter. Yesterday, more than 500 experts from all over the country attended the Chinese Academic Conference on Sexology, where the World Health Organization's findings on humans were announced.