Sperm counts around the world have fallen by more than half since the 1970s, threatening to create a reproductive crisis if the trend continues to accelerate, scientists say. A study published Tuesday in the journal Human Reproduction Update found that the average sperm concentration fell by 51.6 percent between 1973 and 2018, while total sperm counts fell by 62.3 percent in the same period, according to data from 53 countries. Worse still, the rate of decline appears to be speeding up. “I think this is another signal that something is wrong with the globe and that we need to do something about it,” lead author Prof Hagai Levine of the Hebrew University of Jerusalem told The Guardian. “I think it’s a crisis that we better tackle now, before it may reach a tipping point which may not be reversible.”