But that is only half the story. Possibly even less, according to mounting evidence. Male fertility is dipping, and fast. Sperm may prove to be the greatest casualty of modern life.

Last summer, scientists at the Hebrew University of Jerusalem found that male sperm counts had fallen by almost 60 per cent in 40 years. In what was the largest study of its kind, they analysed data from 43,000 men from North America, Europe, Australia and New Zealand, taking in 185 studies from 1973 to 2011. Its lead author, Dr Hagai Levine, decreed the result an 'urgent wake-up call'.