Gender selection involves a variety of theories and methods, including dietary conditioning (alkaline foods tend to produce boys, acidic foods tend to produce girls) and AA techniques (scheduling the ovulation day tends to give birth to a boy, and scheduling a few days before the ovulation day tends to give birth to a girl). Accurate determination of ovulation day is critical to implementing these methods and can be achieved through menstrual cycles, ovulation test strips, follicle monitoring and basal body temperature measurements.