How Different Gender Conception Calculators Work

Illustration of sperm rushing toward an egg

If you are trying to conceive, a gender conception calculator may help you choose the gender of your baby. While many will say that you have a fifty percent chance of conceiving a boy or a girl no matter what you do, there are a few theories that suggest conceiving a boy or girl is a matter of timing when you have intercourse.

Shettles Method

Dr. Landrum Shettles created the Shettles Method for gender selection. His book, How to Choose the Sex of Your Baby, describes the characteristics of sperm carrying the X and Y chromosomes that yield a girl or boy. According to Dr. Shettles, sperm carrying the Y chromosome are small and fast but have a shorter life span. Sperm with the X chromosome are larger and slower but live longer. His theory is that if a couple desires a boy, intercourse should occur the day before or the day of ovulation. This will help ensure that the Y chromosome sperm will reach the egg first. To conceive a girl, intercourse should occur two and a half to three days prior to ovulation. According to the Shettles Method, intercourse occurring this early will allow the Y chromosome sperm to die off, but the X chromosome sperm will survive to fertilize the egg, resulting in the conception of a baby girl.

Gender Conception Calculators

If you can determine the average length of your cycle and your approximate ovulation date, you can use an online conception calculator to help you predict the days intercourse should occur to conceive the baby of your desired gender. These methods are not scientific, but more based on old wives' tales.


iBabydust can help you find the appropriate dates to engage in intercourse in order to conceive a particular gender. First, you will need to enter the first day of your last period, along with the average number of days in your cycle. The ibabydust calculator will create a fertility calendar for you based on your desire to conceive a boy or a girl.

Chinese Gender Calendar

The Chinese conception chart, or Chinese Gender Calendar, is a chart that uses your age at conception and conception month to determine your baby's gender. While this method is much less involved than the more scientific Shettles Method, some do believe it is accurate. However, the medical community has not performed any studies to verify these claims. Using the Chinese gender calendar, find your age along the left side of the chart and match it with the month at the top when you wish to try to conceive. Match up the age with the month of conception to discover the gender predicted for that month. If the gender you want to conceive doesn't display in the box, follow the line across until you find the month that the gender is listed and try to conceive during that time.

Conceiving a Specific Gender

Methods to conceive one gender or the other are not guaranteed to work, even if you follow the method precisely. Although no gender conception calculator or calendar provides absolute assurance, you may be able to increase your chance of fulfilling your dream to add pink or blue to your home with these calculators.

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How Different Gender Conception Calculators Work