Pituitary tumors are not born. Nowadays, the factors of pituitary tumors are of a doctrinal nature, which in general terms are uncertain, unlike smoking that causes lung cancer or hepatitis B that causes liver cancer, etc., where there are clearly proven factors. However, there is no obvious causative factor for pituitary tumor, there are very many theories: 1, mainly genetic factors, that is, genetic aspects of the family has hereditary; 2, mainly exposure to certain radioactive radiation factors; 3, with some chemical drugs, such as formaldehyde after renovation, etc.; 4, unexplained onset. There is no complete research, so you can also get pituitary tumor later in life.