Testis has both endocrine and gametogenic functions which are controlled by gonadotrophic hormones secreted from pituitary. The glandular part of the testis consists of 200–300 lobules containing seminiferous tubules and the loose connective tissue containing contractile peritubular myoid cells and clusters of steroid producing Leydig cells. They synthesize and secrete the male sex steroid hormone testosterone under the influence of pituitary LH. The first spermatozoa are released at puberty, but these represent the culmination of events that begin early in fetal life. In the seminiferous tubule there are two types of somatic cells—the myoid or smooth muscle like cells and sertoli cells, and different types of germ cells- spermatogonia, primary spermatocytes, secondary spermatocytes, round spermatids, elongating and elongated spermatids. Theoretically each primary spermatocyte produces four spermatids, but some may degenerate during maturation. A small residual cytoplasmic droplet also remains attached to testicular spermatozoa at the point of separation. As the cell undergoes further maturation during epididymal transit this cytoplasmic droplet migrates along the tail and is finally lost. Consequently a period of 10 to 12 weeks is required for the production of human spermatozoa from germinal stem cells to a stage where they are ready to be ejaculated. The epididymis has following major functions: sperm transport, sperm concentration, sperm storage. Congenital absence of vas deferens is usually associated with agenesis of seminal vesicles due to their common embryonic origin. Prostatic fluid also enhances the motility of epididymal and ejaculated spermatozoa by contributing certain factors like albumin. The primary function of this secretion is to lubricate the urethra, which is probably better expressed as the neutralization of any acidic urinary residue in the urethra before ejaculation. The radially arrayed sperm aster is adjacent and affixed to the sperm nucleus. It helps in pushing the two pronuclei until they appose in the center of the oocyte. This event is followed by the breakdown of the nuclear envelope and fusion of the pronuclei. Simultaneously the centrosome duplicates and separates, originating the two poles of the first mitotic spindle. The chromosomes from male and female gametes are released into the ooplasm and get mixed as they align at metaphase plate of the first mitotic spindle. At this stage the first cleavage division begins resulting in production of zygotic nucleus that contains chromosomes of maternal and paternal origin.