There are two types of hypogonadism that are classified depending on the cause of the condition. In both types, hypogonadism is caused when the sex glands produce too little hormones. In primary hypogonadism, this is a result of problems with the function of the sex glands (ovaries or testes) themselves. Primary hypogonadism may be caused by certain genetic disorders, infections that affect those glands, or radiation treatment. The other type of hypogonadism is called secondary, or central, hypogonadism. This type is caused by problems in the parts of the brain that control the sex glands - the hypothalamus and pituitary. Causes of secondary hypogonadism may include tumors, genetic problems, infections, or rapid weight gain or loss. Both types of hypogonadism generally cause the same symptoms, but symptoms vary according to a person's age when they develop the condition.