The human androgen receptor gene contains polymorphic CAG region in first exon. Androgen receptor activity increases or decreases in correspondence to CAG length. This leads to various pathological states including neuro-muscular diseases, androgen related diseases, and carcinomas. Molecular biology as a scientific branch develops constantly, therefore number of studies using its techniques rapidly increases. In this paper we concentrated on most recent studies on androgen receptor gene polymorphism especially in relation with detection of estrogen dependent cancers such as breast cancer, ovarian cancer or endometrial cancer. Clinical value of this method is very promising, but further studies are needed.