Sperm counts among men have more than halved in the last 40 years, research suggests, although the drivers behind the decline remain unclear.
The latest findings reveal that between 1973 and 2011, the concentration of sperm in the ejaculate of men in western countries has fallen by an average of 1.4% a year, leading to an overall drop of just over 52%.
“The results are quite shocking,” said Hagai Levine, an epidemiologist and lead author of the study from the Hebrew University of Jerusalem. While infertility treatments such as IVF can offer solutions to potential ramifications of the decline on one level, little has been done to address the root of the issue, said Levine, pointing out low sperm counts might also be an indicator of poorer health among men more generally.
“This is a classic under the radar huge public health problem that is really neglected,” he said. It is not the first time researchers have highlighted concerns about sperm counts, but previous studies have been criticised, with some saying the decline could be down to changing laboratory methods, or studies failing to take into account whether participants were selected on the basis of infertility problems.
But the authors of the latest study say they have addressed such concerns, analysing only studies that used the same sperm count method, were of a reasonable size and involved men not known to have infertility problems or disease, among other measures. “If you are a guy with a low sperm count and you try for a baby when you are 21, you are probably not going to notice you’ve got a problem,” Pacey said. “But if you are trying with your partner when she is 35 then that’s when the heartache comes, because by then you have got low sperm count, you’ve got an older partner and you haven’t got a lot of time to try and fix it medically.”