Choosing your baby's sex: What the scientists say

Of course, this list may not necessarily include your great grandmother's "tried and true" formula for choosing the baby's sex. Some doctors just chuckle at such schemes and say that as long as the advice doesn't hurt mom or baby, then there may be no harm in trying.

Natural Methods for Choosing the Sex of Your Child

The Shettles method is arguably the most well-known natural strategy for choosing the sex of your child. Developed three decades ago by Landrum B. Shettles, MD, PhD, the plan involves timing intercourse to a woman's cycle and assuming certain sexual positions.

In his book How to Choose the Sex of Your Baby, Shettles explains that the male (Y) sperm is smaller, faster, and more short-lived than the female (X) sperm. Because of this, it is better for boy-desiring couples to have sex closest to the time when a woman's egg is released (ovulation). This way, the speedy male sperm could get to the egg sooner than the female one.

The Y chromosome apparently also enjoys an advantage over its counterpart when the sperm is discharged as close as possible to the opening of the cervix. This is achieved through rear entry intercourse (man enters woman from behind).

Parents desiring a girl, on the other hand, are encouraged to have sex in the missionary position (face to face, man on top) about two to four days before ovulation so that by the time the egg comes, only the heartier, more resilient X sperm will remain in the woman's reproductive tract.

The Shettles method has reportedly been effective at least 75% of the time, with the rate slightly lower for girls than for boys. Pat Buie, a registered nurse from Canada, incorporated Shettles' method into her sex selection plan -- described in her book Choose the Sex of Your Baby Naturally -- and claims to have a 95% success rate