An estimated 2.6 million couples in the United States experience problems with fertility, and numerous factors may be involved in both the male and the female partners. In up to 40% of infertile couples, male factor infertility plays a contributing role. For many years, the evaluation of male infertility has relied on-and been limited to-semen analysis, which measures sperm count and assesses sperm motility and morphology. More recently, new technologies have evolved that measure DNA fragmentation in sperm. Clinical studies have shown that sperm with elevated levels of DNA fragmentation are a strong predictor of reduced male fertility. Many factors-infection, diet, illicit drugs, some prescribed and over-the-counter medications, lack of sleep, stress, high fever, elevated testicular temperature, air pollution, alcohol, cigarette smoking, toxin exposures, advanced age-may result in DNA fragmentation.Now on the market is a dietary supplement called Proxeed?, which has been designed to enhance and support the quality of sperm. This supplement provides ingredients that contribute to the metabolic processes in the cells that manufacture sperm. Clinical data have shown that the ingredients in Proxeed? may potentially optimize sperm motility, speed, count, morphology, and concentration.Recently, Mark Perloe, MD, an endocrinologist and fertility specialist, posed questions to Phillip Werthman, MD, a board certified urologist and fellowship-trained andrologist, on the use of DNA testing of sperm, on the implications of DNA fragmentation, and on the benefits of dietary fertility supplements in optimizing the reproductive health of men. The following is a report of Dr. Werthman’s answers to these questions.