Men who eat a diet rich in fruit, vegetables and fish could boost their chances of becoming a father, according to a new study.
A Mediterranean-style diet, which also contains leafy vegetables, pulses and whole grains, can enhance sperm motility by 11per cent.
This could be especially important for couples who are trying to conceive naturally.
The research comes as a separate study found that men who take moderate exercise can also positively impact their sperm motility.
Both studies were presented at the American Society for Reproductive Medicine conference in Orlando.
In the first, experts from universities including the Harvard School of Public Health, examined the diets of more than 180 men aged 18 to 22.
They split those who ate any Mediterranean-type items into four sub-sets, from those with the highest intake of these nutrient-rich foods to those with the lowest.
Those in the highest group had an increased sperm motility of 11 per cent compared to the lowest.
Audrey Gaskins, from Harvard’s Department of Nutrition, said: “I think motility is most important for couples who are trying to conceive naturally.
Edward Kim, from the Society for Reproduction and Urology, said: “There is no doubt that motility is one of the most important parameters that we look at in semen quality.
“These findings are intriguing and will compel us to do further studies in this area.”
Allan Pacey, senior lecturer from the academic unit of reproductive and developmental medicine at the University of Sheffield, said the influence of a man’s diet on semen quality had been of interest for some time.
“For example, there is now good evidence from a variety of studies that men with a higher antioxidant intake have slightly better semen quality and are more likely to become fathers than men who don’t.”
In the second study, from experts at Yamaguchi University in Japan, 215 men attending an IVF clinic completed a questionnaire about their exercise habits and gave semen samples.
This was then translated into “metabolic equivalent” hours per week based on the type of exercise, frequency and duration.
Men were given a score based on whether they did strenuous, moderate or light exercise.
Dolores Lamb, president-elect of the ASRM, said: “Exercise is a component of an overall healthy lifestyle, which contributes to reproductive health.
“This study which uses frequency, intensity, and duration to quantify the amount of exercise a subject gets, shows that a moderate exercise routine may be recommended to modestly improve semen parameters in men, with no known conditions that impair their reproductive capacity.”