(1) Animals may reproduce by asexual or sexual modes to maintain continuity of the species. (2) The human male reproductive system consists of paired testes in the scrotum, epididymis, vas deferens, a urethra which passes through the penis, and the associated glands: a prostate gland, two seminal vesicles and Cowper’s glands. (3) The human female reproductive system consists of two ovaries, two Fallopian tubes, a uterus and a vagina. (4) The primarily male sex hormone is testosterone. The female sex hormones are estrogen, and progesterone, production and release of these sex hormones are regulated by FSH, LH, and LTH. (5) The menstrual cycle consists of cyclic changes in human female from puberty to menopause, usually 28 days per cycle. The cycle consists of various phases, controlled by hormones, and it culminates into a menstrual flow of blood from the vagina. (6) Early development begins with fertilization of the ovum by the sperm sucessive cleavages result in the formation of a morula then a blastula. The blastula or the blastodisc implants in the uterus and then undergoes the process of gastrulation to form 3 germ layers, i.e., ectoderm, mesoderm and the endoderm. Definite organ systems are formed from each of these layers.