A healthy woman has regular 28-day menstrual cycles, but her husband has low sperm counts. The best timing of IUI for this woman would be on

Normal sperm survive in the female reproductive tract for at least 3 days, but an oocyte survives only for 12–24 hours. If ovulation is expected on day 14 and if only 2 inseminations are to be performed per month, then day 12 and 14 would be preferable for IUI.