//wasana.news. {fitness and lifestyle}; Male fertility decline; infertility is defined as a couple's inability to get pregnant for one year despite regular intercourse. When this is the case, doctors evaluate both partners to determine why For men, the cornerstone of the fertility evaluation is semen analysis, and there are a number of ways to assess sperm. Sperm count, which is the total number of sperm a man produces, and sperm concentration — number of sperm per millilitre of semen — are common measures, but they aren't the best predictors of fertility. A more accurate measure looks at the total motile sperm count, which evaluates the fraction of sperm that are able to swim and move. A wide range of factors — from obesity to hormonal imbalances to genetic diseases — can affect fertility. For many men, there are treatments that can help. But, starting in the 1990s, researchers noticed a concerning trend. Even when controlling for many of the known risk factors, male fertility appeared to have been declining for decades. By RYAN P SMITH, UNIVERSITY of VIRGINIA, USA. {PHOTO:INTERNET}.