Men’s average testosterone levels have halved over the past 50 years, according to scientists, who say society is facing a male fertility crisis. Ian Sample speaks to science correspondent Hannah Devlin to find out how the work has been received and what the researchers want to see happen in response to their finding

Exclusive: Researchers warn of ‘major crisis in male reproductive health’ partly driven by obesity and diabetes

Men's testosterone levels have dropped by 50% in 50 years, with scientists linking the decline to rising obesity and diabetes, sparking concerns over male fertility.