I have always been fascinated by the exquisite design of biological systems. The more we humans understand about biology, the more we realize we don’t know. The process of mammalian fertilization is one of these complex biological systems that in nature requires the proper coordination of so many factors ranging from the behavior of male and female to biochemical changes at the cellular and molecular level. Defined as: “A process in sexual reproduction that involves the union of male (sperm) and female (ovum) gametes (each with a single, haploid set of chromosomes) to produce a diploid zygote”, fertilization requires that functionally viable sperm, at the right stage of maturity, are present in the oviduct of the mare during a brief window of time when a functionally viable oocyte is present.