coital frequency การใช้

• Chapter 7 : " Fecundability and Coital Frequency ".
• The U . N . estimate of 10 billion and Population Action's 8 billion were both based on a 2000 study by the Johns Hopkins University School of Public Health, which used population figures for men ages 15 to 59 and " coital frequency surveys " from many sources, including anthropologists, aid agencies and a condom company.