Couch potato men have less chance of becoming dads, according to new research. Lazing about in front of the telly instead of getting out and about significantly reduces sperm count.
The results have been described as 'truly exciting' because men can take their futures into their own hands simply by exercising.
The findings, in the British Journal of Sports Medicine, revealed that men who watched more than 20 hours of TV weekly had a 44 per cent lower sperm count than those who were active. And men who exercised for 15 or more hours weekly at a moderate to vigorous rate had a 73 per cent higher sperm count than those who exercised less than five hours each week.
Doctoral student Audrey Gaskins at Harvard School of Public Health said finding 'two potentially modifiable factors' was 'truly exciting'.
Assistant professor of nutrition and epidemiology Jorge Chavarro added: "The majority of the previous studies on physical activity and semen quality had focused on professional marathon runners and cyclists, who reach physical activity levels that most people in the world cannot match."We were able to examine a range of physical activity that is more relevant to men in the general population."