According to WHO (World Health Organization), an ejaculate is considered normal if at least 1.5ml of ejaculate contains more than 15 million sperms per milliliter of semen. Out of these at least 32% should swim in a forward direction, and at least 4% should have a normal shape. Given that these criteria are met, a man is considered fertile. In order to be certain, the ejaculate should be evaluated twice. Apart from the findings of semen analysis, an ejaculate should not contain more than 1 million white blood cells and microorganisms per mL ejaculate. If the semen analysis is abnormal and does not meet the WHO (World Health Organization) criterion, then further intervention is required. The WHO criteria changes at times however the sperm concentration criteria have been the same for a long time now, which is; there should be at least 15 million sperm cells per mL and the ejaculate volume should be at least 1.4 mL.