A principal role of the sperm is to serve as a vessel for the delivery of paternal genetic material to the oocyte. Following penetration of the cumulus complex and zona pellucida by the sperm, the sperm membrane binds to and fuses with the oolemma triggering oocyte activation, which results in the resumption of meiosis, extrusion of a second polar body, and formation of male and female pronuclei. Subsequently male and female pronuclei migrate together and fuse to form a single, diploid pronucleus that will undergo replication and undergo multiple rounds of mitosis to form an embryo that will, under ideal circumstances, result in a healthy offspring. Successful sexual reproduction depends on, among other factors, a normal sperm genome. Aberrations in the sperm genome including DNA damage, aneuploidies, gene mutations, and structural variations can result in failed fertilization, arrested or abnormal embryo development, early or late miscarriage, or in rare cases the birth of genetically abnormal offspring. This chapter will discuss the known sperm genetic abnormalities that can impact embryogenesis, pregnancy, or offspring health. A brief review of the events required for successful spermatogenesis and fertilization is important in understanding how the complete sperm genome arises and how insults at different stages in development can lead to genetic anomalies that can be transmitted to the embryo.
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