What is the reason of endometriosis? Is it because of birth control pills?

Endometriosis is a painful condition in which the tissue that normally lines the inside of the uterus, called the endometrium, grows outside of the uterus in other parts of the body such as the outer surface of the uterus, the ovary, fallopian tubes, and bladder. The exact cause is unknown though genetics or hormonal irregularities may contribute. Birth control pills can help reduce the pain associated with endometriosis and are a common treatment option.