A gonad or sex gland or reproductive gland is an endocrine gland that produces the gametes (germ cells) of an organism. In the female of the species the reproductive cells are the egg cells, and in the male the reproductive cells are the sperm. The male gonad, the testicle, produces sperm in the form of spermatozoa. The female gonad, the ovary, produces egg cells. Both of these gametes, are haploid germ cells.