All the glands in the human body comprise the endocrine system. They produce hormones essential for making the body function properly. If the endocrine system is not working properly, a person's ability to develop correctly during puberty, procreate or get pregnant, as well as manage stress, are impaired.
In the male body, the gonads or testes as they are more commonly known, are also considered as endocrine structures in addition to their being part of the male reproductive system. They produce testosterone, a male hormone that is responsible for making hair grow on the face and body during puberty. Testosterone also helps the penis become enlarged. It also plays an important part in the production of sperm.