Leydig cells are found adjacent to the seminiferous tubules in the testicle. They produce testosterone and spermatogenesis in the presence of luteinizing hormone ( LH ). The placenta secretes extra ovarian hormones-oestrogen and progesterone in female during pregnancy that serves to maintain foctus. It also secrete hCG,hPL and relaxin. The corpus luteum secretes large amount of progesterone which is essential for maintenance of endometrium. Graafian follicles of ovary secrete oestrogens and progesterone to control the growth and functions of female secondary sex organs. Thus, primary sex organs control the growth, function and maintenance of secondary sex organs.