Fatty acids, particularly omega-3 and omega-6 polyunsaturated fatty acids, have scientific evidence supporting a role in testicular health and function. Animal and human studies indicate that these essential fatty acids are crucial for the development and maintenance of testicular structure, spermatogenesis, and steroidogenesis. For instance, research has shown that diets deficient in omega-3 fatty acids can lead to impaired sperm motility, decreased sperm count, and abnormal sperm morphology in both animals and humans. Conversely, supplementation with omega-3s (such as EPA and DHA) has been associated with improved semen quality and increased testicular antioxidant capacity.

The mechanisms proposed include the incorporation of fatty acids into sperm and testicular cell membranes, modulation of inflammatory responses, and influences on hormone synthesis, notably testosterone. Some clinical trials and observational studies in men have found correlations between higher dietary or blood levels of omega-3 fatty acids and better semen parameters. However, most of the evidence is moderate in quality, with some studies showing benefit and others finding minimal or no effect. There is less evidence supporting a role for saturated fats or trans fats, which may negatively impact testicular health.

In summary, there is a moderate level of scientific validation for the use of fatty acids, especially omega-3s, in supporting the testes and male reproductive system, though more high-quality human trials are needed for stronger recommendations.