Studies in rodents have demonstrated a critical role for the circadian clock in gating the timing of the pro-estrous LH surge and ovulation: both ablation of the master circadian clock in the suprachiasmatic nucleus (SCN) of the hypothalamus and disruption of the neural connections between the SCN and preoptic area eliminate estrous cyclicity and cause infertility in rats [1]. The gene discussed is CLOCK; the disease is Infertility.