For as long as women have been having babies, people have been coming up with ways to influence the sex of their unborn child. From drinking Pepsi and gorging chocolate, to making love under a full moon, couples who would give anything for a daughter or a son have given some of the 'old wives' methods a shot.

Of course, none of these have been endorsed by the medical community and debate continues over whether it's even ethical to choose the sex of your child. Nevertheless, supporters of these somewhat dubious sex selection methods swear by them, especially if they had gotten what they wanted.

The rather miraculous process of human reproduction is surrounded in mystery and myth. Theories abound regarding how to improve fertility, treat morning sickness and induce labor. Predicting the gender of your baby is another area filled with knowing opinions based largely in folklore and intuition.

Myths regarding how the gender of your baby is determined probably have their roots in at least two faulty assumptions. One is the concept that past events alter future ones. For example, the chances that a couple will have five boys in a row is one in 32 (or about three in 100); but with each individual child, the chances of having a boy are one in 2 (50 percent), even if the couple already has four sons. Another assumption is that when something unusual happens (for example, having five boys in row), there must be an explanation that is separate from the normal state of affairs. Although unusual things do happen, they do not imply that the laws of nature should be repealed.

Despite what you may have heard, there is relatively little a couple can do through naturally occurring conception - to change gender of your baby. Many people believe that position during intercourse, diet, the lunar cycle or gender patterns in the couple's families all contribute to the gender of your baby. In fact, these factors have no well-established effect.

However, the timing of intercourse can have an effect on the gender of your baby. Sperm carrying Y chromosomes apparently swim faster but do not survive as long as their X-carrying counterparts. So if a couple has intercourse right at the time of ovulation, the faster-swimming male sperm has an advantage and the gender of your baby is slightly likely to be male. But if the timing is a day or two earlier, more of the male sperm die out, and the gender of your baby is a bit more likely to be female baby. Even so, it is often difficult to time ovulation accurately, and your odds of determining gender do not change much. Without the application of advanced (and sometimes invasive and expensive) technology, such as in vitro fertilization, the chances of the gender of your baby remain close to equal. There is no way to know the gender of your baby without scanning or technical procedures. Moreover, scanning and other procedures for the purpose of finding out your baby's sex are illegal.

If you have a strong preference for a boy or a girl, your options are limited. You could plan to have enough babies so both genders are eventually represented. Or it may be better to rethink your position and hope for a healthy baby of either sex.