ESR1 and Infertility: In a review article by O'Flynn O'Brien et al. (2010[21]) on the genetic causes of male factor infertility they concluded that there is a need for further examination of ER genes polymorphisms to reproduce the results of previous uncoordinated studies and to better explain the influence of these polymorphisms on male fertility (O'Flynn O'Brien et al., 2010[21]; Safarinejad et al., 2010[26]).