ESR2 and Infertility: In the comparison between eutopic fertile (group 2A) and eutopic infertile (group 2B) patients, markedly higher (P < 0.0001) levels of the STAR, CYP19A1, ESR2 and PGR transcripts and higher (P < 0.01) levels of the PRA protein were observed in fertile patients (group 2A) than in infertile patients (group 2B).