The Finns are known to have the highest sperm counts in the world and appear to have escaped the falling sperm counts and abnormalities of the reproductive tract which are being reported from the rest of Europe. These have been linked with chemicals, such as the phthalates at the centre of the baby milk row, which mimic the female hormone oestrogen.
However, the new study speculates that the "Finnish exception" to falling sperm rates may be due to lower rates of maternal smoking in Finland compared with the rest of Europe.
The study by Dr Michael Joffe, a senior lecturer in public health at Imperial College, London, is significant because it assessed how long it took couples to get pregnant as a measure of fertility, rather than sperm counts or motility which are difficult to compare.
"It is the first time that someone has shown a change in fertility as well as a change in sperm quality," Dr Joffe said yesterday.
To test the hypothesis that Finnish males are more fertile than British males, Dr Joffe compared "time to pregnancy" data from two different studies in each country carried out between the early 1980s and 1991.
According to a report in tomorrow's issue of the Lancet, fertility was statistically significantly greater in Finland than Britain. Dr Joffe concludes: "The previously reported difference in sperm counts between Finland and elsewhere in north-west Europe is probably not artefactual, suggesting that the reported worldwide decline in semen quality is also real."
Dr Joffe said more research was needed to establish the reasons for the differences in male fertility between Finland and the rest of Europe.Reuse content