The direct benefits of this study will be to know whether the endometrial gene expression profile is modified in response to stimulation treatment and have an impact or not on the endometrial tissue receptivity. The potential benefits of this study could be to assess the therapy optimization based on individual treatment response and gene expression profile compared to group treatment response in infertile women and prediction of response to therapy based on gene expression profiling before and after Gonal-f® stimulation in infertile women.