In conclusion, we propose that the presence of at least two LH pulses over 4 h, an LH response to GnRH ≥ 33 UI/l, or inhibin B plasma levels ≥ 63 pg/ml can accurately predict the resumption of menses in weight-normalized but persistently amenorrheic patients with anorexia nervosa, provided there is no weight loss or intense exercise. This evidence concerns the gene GNRH1 and anorexia nervosa.