Selenium is an essential trace element that plays a critical role in the reproductive health of both men and women. Scientific studies have shown that selenium is involved in the synthesis of selenoproteins, some of which are crucial for protecting cells from oxidative stress, including sperm cells and ovarian tissue. In men, selenium is particularly important for sperm motility, morphology, and overall fertility. Several clinical trials and observational studies have reported that low selenium status is associated with poor semen quality and reduced male fertility. Supplementation with selenium, often combined with other antioxidants, has shown modest improvements in some sperm parameters, though results are inconsistent and benefits are most evident in men with selenium deficiency or subfertility.

In women, selenium is also important for reproductive health, with research suggesting roles in early embryonic development and possible protection against pregnancy complications such as preeclampsia. However, the evidence in women is less robust, and most of the data are preclinical or observational in nature. Excessive intake of selenium can be harmful, so supplementation should be approached with caution. Overall, while there are scientifically plausible reasons for selenium to support reproductive health, especially in deficient individuals, high-quality randomized controlled trials demonstrating clear benefits are limited, leading to a moderate evidence rating.