Being overweight and eating an unhealthy diet may have a negative effect on a man's fertility, according to Zita West, fertility and pregnancy expert and founder of the Zita West Clinic.
Ms West suggested that men who are concerned about their fertility should aim to be a healthy weight and avoid processed, high-fat foods.
She said: "If a man is overweight, there is a lot of heat around the testes which can affect the hormones et cetera [and] processed foods and trans fats [can have a negative impact on fertility".
Women also need to consider that in order to optimise their fertility, they should be eating a balanced diet, which maintains blood sugar levels, she said.
She suggested that a diet which is rich in antioxidants will help to neutralise the potentially damaging effects of free radicals on the body.
A recent study led by the University of Southampton, and involving teams from Singapore and New Zealand, revealed that a woman's diet during pregnancy may have an effect on the likelihood of that child becoming obese.