The document summarizes key aspects of male human anatomy and physiology related to sex and reproduction. It describes the 46 human chromosomes including the sex chromosomes XX or XY. The SRY gene on the Y chromosome determines male sex. During fetal development, hormones like testosterone direct male sexual differentiation. In adulthood, testicles produce 95% of testosterone which supports sperm production and secondary sex characteristics. The process of sperm development, sexual arousal, and ejaculation are outlined.