Williams CL, et al. - In this large, population based, data linkage cohort study, researchers examined the risks of ovarian, breast, and corpus uteri cancer in women who have had assisted reproduction. Study participants were all women who had assisted reproduction in Great Britain from 1991-2010, as recorded by the Human Fertilisation and Embryology Authority (HFEA). In women who had had assisted reproduction, elevated risk of corpus uteri or invasive breast cancer was not seen, while increased risks of in situ breast cancer and invasive and borderline ovarian tumors were. Increased risks of ovarian cancer were limited to women with endometriosis, low parity, or both. No increased risk of any ovarian tumor in women treated was found because of an only male factor or unexplained infertility.