Your TTC Strategy 4: Understand Genetics and Gender Selection

People throughout history have wished they could choose a baby's gender rather than leaving it to chance. As early as 330 BC, Aristotle prescribed the tying off of the left testicle in men wishing to have boys. Aside from the ethical issues of gender selection in cultures that place a higher value on boys, there can be advantages to choosing your baby's gender, such as achieving the vision of the perfect family and avoiding sex-linked genetic diseases. That last issue in particular makes it important to understand the basics of genetics, and whether (and how) you should try for a girl or a boy, well before you start the process of trying at all.

Henry VIII, who discarded five wives who failed to provide him with a male heir, did not know that it was actually he who determined the sex of the offspring. There are two kinds of sperm: X and Y. If an X chromosome-bearing sperm fertilizes the egg, a girl is conceived; if a Y chromosome sperm does the job, a boy is conceived. Semen contains virtually equal numbers of X and Y sperm. Even fathers of all boys or all girls have both X and Y sperm!

People have tried everything from folk remedies to drugstore kits to tip the scales in favor of having a child of a particular sex. Some people believe that timing conception according to calendar readings can influence a baby's sex. A 13th century Chinese conception chart purports to be able to identify the sex of the baby before birth. (Try it for yourself, here.) Because even implausible and ineffective methods have a "success" rate of 50 percent, many continue to be recommended by word of mouth.

The most commonly used method of influencing the baby's sex is by carefully timing intercourse with respect to ovulation. The time of ovulation can be determined by cervical mucus changes, urine LH testing, occurrence of Mittleschmertz (ovulation pain), or basal body temperature changes. One of the most popular is the Shettles Method, which is based on the fact that male and female sperm travel and survive in the reproductive tract for different amounts of time (the males swim faster, but run out of energy sooner than female sperm). For a boy, intercourse should be timed about 12 hours prior to ovulation and for a girl, several days before ovulation.

Other sex selection techniques that have been popularized include, but not considered reliable:

• altering the vaginal pH (an acidic environment favors girls and an alkaline environment—as at ovulation, when the pH balance changes—favors boys)
• depth of penetration (deep ejaculation favors boys, especially on the day of ovulation)
• sperm count (a high count favors boys)
• testicular temperature (boxers for boys, hot bath immediately before intercourse for girls to kill off the weaker Y-bearing sperm)

It is thought that minerals in your diet affect the metabolism and environment of the egg and therefore make it more attractive to sperm of one particular sex.

If you want a boy, eat plenty of potassium-rich foods such as meat, bananas, apricots, and celery. Learn more boy-conception theories here.

If you want a girl, opt for lots of magnesium-rich foods such as nuts, soybeans, and leafy green vegetables should do the trick. Check out these girl-influencing tips.