They believe that lycopene, which gives tomatoes their bright red coloring, can turn sperm into supersperm.
Researchers at the University of Portsmouth studied the effect of lycopene in the diet on a random group of six healthy men, with an average age of 42.
They were asked to consume a 400g tin of Heinz cream-of-tomato soup every day for two weeks.
Sperm samples taken from them over the duration over the study, the first of its kind, revealed a marked increase in levels of lycopene.
How this affects fertility needs further research, but it is known that infertile men have lower levels of lycopene in their sperm.
It is thought the compound may mop up harmful chemicals in the body called free radicals which can play a part in infertility.
The researchers from the university's biomedical science department said further studies should be carried out to discover whether the same boost would be seen in infertile men.
Tomato products are already thought to lower a man's risk of prostate cancer because of the high concentration of lycopene.
The powerful antioxidant is better absorbed when tomatoes are processed, as in soup.
This is because lycopene is bound to the fruit's cell structure, and released by the processing.
