00:00:0000:00:00Men’s average testosterone levels have halved over the past 50 years, according to scientists who say society is facing a male fertility crisis. Rising levels of obesity and diabetes are expected to play a part, but the team behind the work suggest that environmental factors such as endocrine-disrupting chemicals – which can be found in various household items – and global heating could also be factors in the apparent striking decline. 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 findingMore on this storyMore on this storySnip happy: five men on their choice to get a vasectomyMen’s average testosterone levels have halved in last 50 years, say scientistsWorld’s largest GPS penis traced across Bannau Brycheiniog for charityScientists find humans age dramatically in two bursts – at 44, then 60Call for action on UK men’s health as 133,000 die early every year double quotation markBeards are alpha, ‘rat boys’ are in – and the rules of masculinity are as baffling as everdouble quotation markGareth Southgate has proved that quiet competence can lift a nation – it’s a lesson that goes far beyond sportScience Weekly‘Spermageddon’: is male fertility really in crisis? – podcastdouble quotation markMen are less able to identify eating disorders – I called mine ‘cutting weight’Cash incentives may help men lose weight, research findsMost viewedMost viewed