Genetics play an important role in the evaluation of the infertile male. The current limitations of classifying the genetic contribution to male infertility and the importance of phenotyping men are discussed, and the core concepts necessary to interpret most genetic studies are reviewed. The current genetic assays used clinically are discussed in detail. The use and interpretation of the cystic fibrosis transmembrane receptor assay are examined in the context of men with clinical bilateral absence of the vas deferens, a karyotype and Klinefelter syndrome, and Y chromosome microdeletions. The role of hormones and epigenetics in evaluating the genetic reproductive potential of men is discussed briefly. A summary of what the field might look like in 2034 is presented.