Humans could face a reproductive crisis if action is not taken to tackle a drop in sperm count, researchers have warned after finding the rate of decline is accelerating.
A study published in the journal Human Reproduction Update, based on 153 estimates from men who were probably unaware of their fertility, suggests that the average sperm concentration fell from an estimated 101.2m per ml to 49.0m per ml between 1973 and 2018 – a drop of 51.6%. Total sperm counts fell by 62.3% during the same period.
Research by the same team, reported in 2017, found that sperm concentration had more than halved in the last 40 years. However, at the time a lack of data for other parts of the world meant the findings were focused on a region encompassing Europe, North America and Australia. The latest study includes more recent data from 53 countries.
Declines in sperm concentration were seen not only in the region previously studied, but in Central and South America, Africa and Asia.
Moreover, the rate of decline appears to be increasing: looking at data collected in all continents since 1972, the researchers found sperm concentrations declined by 1.16% per year. However, when they looked only at data collected since the year 2000, the decline was 2.64% per year.