This review focuses on the effects of dietary omega-3 fatty acids, comprehensive fatty acid profiles analysis, and transfatty acids on male fertility. Mammalian spermatozoa are characterized by a high proportion of polyunsaturated fatty acids (PUFA) and the membrane structure of spermatozoa plays a crucial role in fertilization. Docosahexaenoic acid (DHA, C22:6n-3) and palmitic acid (C16:0) are the predominant PUFA and saturated FA, respectively, in human’s sperm cells. Whether the higher level of DHA is concentrated in the sperm head or tail is variable among different species, human sperm head contains higher concentration of DHA. Dietary FA influence sperm FA profiles and it appears that it is most sensitive to dietary omega-3 PUFA. Although improvements in sperm parameters are a response to omega-3 sources after more than four weeks of supplementation in men diet, time-dependent and dose-dependent responses may explain the failure in some experiments. In human sperm, elevated saturated or tarns-fatty acid concentration alongside DHA low level is a concern. So, Sperm Fat Depression (SFD) may be suggested as a main explanation for men infertility and regulation of sperm FA mean melting point (MMP) is the key factor causing responses by inclusion of omega-3 PUFA.