Are there foods which can make men more fertile?

Maybe: Obesity is associated with lower sperm counts and less motile sperm probably from hormone imbalances and direct heat damage to the testicles from the larger thighs of obese men. Diets rich in antioxidants (fresh vegetables and fruits) may also improve sperm quality.

Diet and fertility: Generally "fertility" as measured by criteria in semen analysis is more dependent on a nutritionally balanced diet, but severe protein/calorie malnutrition can reduce these parameters. There is no food group or single type of addition to diet which can enhance significantly one's fertility capacity.