The decline was 52.4 per cent -- from 99 million to 47 million sperm per millilitre of semen, said the authors. This was still above the range considered "normal" by the World Health Organization -- between 15 million and 200 million sperm per millilitre. The topic is a controversial one, as numerous studies in the past have contradicted one another -- some showing a sperm count decline, and others not. This sidesteps the problem of comparing samples measured with incomparable technologies -- older tests tended to overestimate sperm count. The best way to confirm changes in sperm count would be through long-term surveillance, known as a prospective cohort study, of a group of healthy males.

Source: The Nation Bangkok July 26, 2017 12:22 UTC