Gonads and Ovary - Reproduction
Sexual reproduction is found in all the multicellular organisms. Protozoans also reproduce sexually during certain periods of life. Sexual reproduction in them may or may not involve male and female gametes. Sometimes two mature sexual parents merely join together to exchange nuclear material or merge their cytoplasm.
It is not possible to distinguish sexes in them. The male-female distinction is more clearly evident in Metazoa. The organs that produce germ cells are known as gonads. The gonad that produces the sperm is called testis and that which forms the egg is known as the Ovary.