This chapter provides an overview of the most commonly known genetic aspects of male reproductive medicine with particular focus on clinical presentation and underlying genetic or molecular etiology. The Y chromosome remains one of the most interesting areas of genetic research in male infertility and certainly, the best developed from a clinical standpoint. The androgen receptor gene is located on the X chromosome and has implications for male fertility. Its role is discussed in the chapter summarizing all chromosomal anomalies of androgen metabolism and signaling. Certain forms of male factor infertility can be attributed to a single gene mutation. One such example is the translocation of the SRY gene associated with the 46, XX male syndrome. The significant epigenetic changes that occur to sperm DNA during spermatogenesis create numerous opportunities for errors to appear and propagate with negative impact on fertility.