Modern medicine has long presumed fertility to be the dominion of women, a space ruled by gynaecologists and invasive procedures explained by softly pink pamphlets. 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’.

Sperm studies have historically been piecemeal and played second fiddle to female fertility research, but warning signs have been flashing for years. In 2012 a study of more than 26,000 French men found sperm counts fell by a third between 1989 and 2005. In the UK, a 2007 report published in the Journal of Andrology found that in one British city, sperm counts had declined by 29 per cent in 13 years between 1989 and 2002.