* During mixing of sperm with seminal plasma, epididymal sperm become coated in seminal plasma proteins. These are stripped by the female tract environment. These proteins were the decapacitating agents that were rendering the sperm incapable of fertilization. | * During mixing of sperm with seminal plasma, epididymal sperm become coated in seminal plasma proteins. These are stripped by the female tract environment. These proteins were the decapacitating agents that were rendering the sperm incapable of fertilization. |