The role of Cysteine-rich secretory proteins, Antigen 5 and Pathogenesis-related 1 (CAP) superfamily proteins in sperm function and male fertility GAIKWADAVINASH SATISH 2020 The production of sperm requires the coordinated action of thousands of genes, including many that are poorly understood. This thesis focused on the role of cysteine-rich secretory proteins, antigen 5, and pathogenesis-related 1 (CAP) superfamily proteins in sperm function. Using a combination of genetic models, state-of-the-art imaging technologies and custom written codes based on fluid mechanics principals. I have defined the role of four CAP proteins in male fertility. This research is relevant to the human reproductive medicine, the agricultural sector wherein assisted reproductive technologies are common, and evolution wherein sperm competition is a major determinant.