Infertility impacts approximately one in six couples attempting to conceive; male factor is at least contributory, if not the sole basis, in 50 percent of these couples [1, 2]. Evaluation of the infertile male starts with the history, followed by the physical examination, and is coupled with semen analysis. The synthesis of this information may suggest inherited conditions (usually autosomal recessive) or de novo abnormalities resulting in an aberrant clinical or spermatozoal phenotype [3, 4]. These may be recognized chromosomal abnormalities, specific gene mutations, or qualitative factors that affect spermatogenesis and fertility potential. Identification of a specific genetic mishap may be informative for the patient and his overall health, for the couple and their therapeutic strategies and results, for the patient’s siblings and first-order relatives, and for the offspring that might be conceived. Although these aberrations may limit natural conception, technical innovations, coupled with the evolution of assisted reproductive technology (ART), may allow previously infertile/sterile couples to parent their own biological children. Helping couples also involves informing them, as best we can, the reasons for the infertility – the etiologies of the sperm defect, the basis for vasal agenesis, and the genetic underpinnings of the abnormally shaped sperm. Although thorough clinical evaluation of the infertile male has always been appropriate, proper genetic analysis and counseling may be equally as important. Male reproductive medicine, surgery, and genetics are inextricably intertwined. This chapter reviews the forms of male infertility that have had an identified genetic basis, summarizes the laboratory tests employed for diagnosis, and briefly discusses more recent salient issues, including concerns regarding the impact of paternal age. Three general subdivisions will be employed: genetic disorders affecting sperm production (in essence, quantitative); genetic disorders affecting sperm function (in essence, qualitative); and genetic disorders affecting sperm transport. This is a paradigm that is unusual but helps to provide a visual way of conceptualizing and compartmentalizing the various conditions discussed. Epigenetics, as it relates to male fertility/infertility, will be discussed in Chapter 6.
