However, they are careful to point out this was just a small study, the first to look at links between specific dietary fats and male fertility, and the findings need to be considered in the light of several limitations. These include, for instance, that the data came from food frequency questionnaires and may have missed some foods the men consumed, and there was only one sperm sample per participant. Also, being of cross-sectional design, it can only suggest links, it can't say there is a cause and effect relationship.