Exposure to mobile phone signals can cause a drop in male fertility, a new study suggests. Up to 14% of couples in high and middle income countries experience fertility problems, and males are the cause in about 40% of cases.
A new study by Exeter scientist Fiona Matthews and her colleagues, published in Environment International, showed that being exposed to a mobile phone may cut fertility by 8-9%, which may see many men reaching into their trouser pockets to deactivate the devices that have become near-universal in the developed world.
The new study is a meta-analysis that combines the findings of 10 previous, smaller studies carried out both in vivo - meaning on living people - and also in vitro: using sperm kept in a dish. In total, more than 1500 data points were analysed with the results showing a strong relationship between exposure to phone emissions and a drop in sperm motility (ability to move) and viability (survival rate).
Critically, sperm concentration did not appear to be affected, ruling out, the researchers say, a thermal effect, since elevated testis temperature leads to lower rates of sperm production. Instead, Matthews and her colleagues speculate that the effect might relate to the production in sperm cells of so-called reactive oxygen species, which damage DNA and hit sperm viability.
These are produced when the microwave signals from the phone affect disrupt the energy supply in the sperm cells, causing biochemical stress to which sperm appear to be quite sensitive. The observed effects might also be an under-estimate of the genuine impact since, as the researchers point out, in many cases only relatively short durations of exposure were tested in the data they studied.
They do also acknowledge, however, that no data on rates of smoking or donor age were available, which could have influenced the findings, and judging exactly what qualifies as "exposure" to phone signals is extremely difficult. The good news, though, is that, according to Matthews, the effect ought to be reversible if men minimise their phone use...