Another study conducted in 2012 by L. Lazaros et al. examined the effect of the CYP19A1 variant on infertility treatment in patients with the polycystic ovarian syndrome; in this study, in which 322 Greek women participated, a significant association between the occurrence of 7 repeats in (TTTA)n, CYP19A1 polymorphism, and its effect on gonadotropin treatment was proven [96], This effect is most likely explained by a change in the ratio of androgen to oestrogen; nevertheless, these findings contradict those published by P. Xu et al. in 2013 among 522 cases and controls. This evidence concerns the gene CYP19A1 and polycystic ovary syndrome.