Technically speaking, you can use ovulation to predict your baby’s gender. Using ovulation to predict your baby’s gender has not been proven through scientific study, though. Still, there are compelling medical reasons why you may be able to, with some degree of accuracy, predict your baby’s gender using ovulation. At a minimum, since there are only 2 genders to pick from, you will still have a 50% success rate with any method that you use to predict your baby’s gender.
To use ovulation to predict your baby’s gender, you need to be certain about a couple of factors. First, you need to know exactly when you are going to ovulate. If you are off by a day, it could affect the accuracy of your gender planning. Second, you need to plan intercourse according to what sex you are trying for.
To use ovulation to predict your baby’s gender, look at the day you had sex and the day of ovulation. Sperm can survive up to 5 days inside the woman’s body after ejaculation. Having sex further from ovulation, but still within the sperm survival range, will favor having a girl. Having sex as close as possible to ovulation will favor a boy.
The reason that you can use ovulation to predict your baby’s gender has to do with the nature of the different types of sperm. The sperm that will produce a baby girl tends to be stronger and live longer than the sperm that will produce a baby boy. On the other hand, the sperm that will produce a boy tends to swim faster, and to be more likely to beat the other sperm out in a race. So, it makes sense that if the sperm was present several days before ovulation, that the “boy” sperm would have died off, leaving the “girl” sperm to fertilize the egg. In contrast, if conception occurs closer to ovulation, those “boy” sperm are going to outrun the other sperm.
This method of gender selection is commonly known as the Shettles Method. In addition to the timing of having sex, there are other aspects of your attempt that you need to pay attention to. You can read more about conceiving a girl here and how to conceive a boy here.