Infertility risk could be reduced if males make simple lifestyle changes, according to a fertility expert.
Dr Allen Pacey believes the overall wellbeing of the male partner can "probably tip the balance" in some fertility cases.
He advised males who are struggling to father a child to give up smoking and to wear loose pants, which can aid fertility by improving the quality of sperm cells.
Diet and exercise could also be altered to help the chance of a conception. Men should aim for a healthy weight and eat five portions of fruit and vegetables a day, he added.
Some of the problems associated with male fertility were highlighted in a recent study published by ProXeed Plus.
The research found just 16 per cent of men gave up alcohol when trying to conceive, compared to 41 per cent of women.
In addition, 15.5 per cent of men continued to eat unhealthy food, only 10.2 per cent of men were wearing loose clothing and ten per cent did no exercise.