Reproduction is one of the most important and fundamental properties of living organisms by which every kind of living organism multiplies to form new individuals of it’s own kind. In this process, one generation of living organisms gives rise to the next generation. This process is not essential to the life of any individual but is a function essential for the life of the species. 

The continuity of life has been possible from the time of its origin, millions of years ago upto the present day, only due to the phenomenon of reproduction-in fact, perpetuation of self and of the species is one of the most remarkable features of living organisms. A species is a group of related animals, plants or microbes that can interbreed to produce a fertile offspring. The preservation of species has been made possible because the parents produce offspring like themselves. It is also the means of increasing the population of a species. It plays a major in evolution by transmitting advantageous changes / variations from organisms of one generation to those of the next.

In human beings, the process is one of sexual reproduction, which involves both male and female sexes. The new individual or offspring develops from the fusion cell called zygote, which is formed, by the fusion or union of two specialized cells called germ cells, sex cells or gametes. 

Generally, one of the gametes is active, smaller in size and without any reserve food. This is the male gamete and it is called the sperm. 

The male reproductive system of a man consists of a pair of testes, ducts, accessory glands and a penis. 

The functions of the male reproductive system are: 

1. Production of sperms. 
2. Transmission of sperms to the female. 

The female reproductive system consists of two ovaries (produce ova and female hormones), Fallopian tubes, uterus (muscular organ which supports the fetus during it’s 40 week gestation period before birth), vagina and external genitalia. 

The functions of the female reproductive system are: - 

1. Production of ovum eggs. 
2. Receiving the sperms. 
3. Providing suitable environment for fusion (fertilization) of the egg and the sperm. 
4. Child birth. 
5. Nourishment of the baby with breast milk until it can take a mixed diet.