At the time of ovulation or up to 1-2 days afterwards, carriers of Y (male) chromosomes are supposed to have a better chance, while carriers of X (female) chromosomes are supposed to have a better chance 2-5 days after ovulation.

During ovulation, other methods involve charting body temperature (hotter for a girl, room temperature for a boy) and charting changes in cervical mucus (the Bilings method).

Otherwise, some believe that shallow penetration is better for conceiving girls because X chromosomes are tougher and survive the journey to the egg better. Frequent sex during the days before fertilisation is also supposed to increase the chances of having a girl.