By now, you know, that sexual reproduction involves both the sexes, that is male and female. In this lesson, we’ll study about the sexual reproduction in human beings. We all know that in the course of development, we grow. It means that our bodies enlarge or we increase in our weight, but during adolescence or teenage new sets of changes appear in our body. At this age, general body growth slows down, while the growth of the reproductive tissues increases. This period of adolescence is known as puberty. Some changes that take place during puberty are common to both males and females. While some changes are peculiar to both the sexes. Now the changes, that are common to both males and females are, development of thicker hair in armpits and in genital area. Second, development of thinner hair on legs, arms or even on face. Third, development of pimples, etc. Some changes that occur only in males are, first development of thick hair on face. Second, the voice of the males begin to crack, and third, occasional enlargement and erection of penis either in daydreams or in night. While some changes that occur only in females are, enlargement of breasts. Second, darkening of the skin of nipples at the tip of the breast, third menstruation. These characters, developed in both males and females are called secondary sexual characters. Now you might be thinking that why these are called as secondary sexual characters? Are these linked to the reproduction process? Let me explain! We know, that in sexual reproduction, both the male gamete and the female gamete should fuse. And this fusion in humans occur inside the female body, and for this the state of maturity of both males and females should be identifiable, and it can be identified by identifying these secondary sexual characters. Now, let’s first discuss about the male reproductive system. The main function of the male reproductive system is to produce the germ cells or the sperm, and to transfer them to the female reproductive system.Based on these functions, the male reproductive system is made up of two types of organs, primary reproductive organ and accessory male reproductive organs. The primary male reproductive organs is a pair of testis. They are responsible for the formation of male germ cells or sperms. Interesting fact about these testis is that, they are located outside the human body in a sack, called scrotum sack. This sack maintains the temperature, which is below the normal body temperature, and this lower temperature is required for the formation of sperms. Besides producing the male gametes, the testis play an important role in secretion of a male hormone called testosterone. Testosterone, regulates the formation of sperms. It also brings changes in the appearance in males during puberty. Now, the sperms that are formed in testis are delivered by the two ducts arising from the testis. These ducts are known as sperm ducts or vas deferens. Moving forward, vas deferens combines with urethra, which is a tube coming out from urinary bladder. Thus, we can say, that urethra forms a common passage for both, urine and the sperms. As the sperms pass through the duct, accessory glands like prostate and seminal vesicle at the secretion to the sperms. This fluid like secretion is known as semen. It makes the transportation of sperms easier and provides nutrition to them. Sperms are the smallest cells in the human body. They mainly consists of genetic material. As you can see, that a sperm has three parts; head, middle piece and tail. Looking carefully, you will find that the nucleus of the sperm is present in its head. The middle re,gion of the sperm, provides the energy to swim and the tail helps the sperm to swim rapidly. So, this was the male reproductive system which majorly aims to produce the male gametes and transfer these gametes to the female body.