There are tons of old wives tales out there that you have most likely dismissed as being just a tale, like how the day of conception can determine a baby’s gender. However, this is one tale that actually has scientific evidence to back it up.

If you want a certain sex for your baby, the day of conception can help you to determine what sex your baby will be.

What Determines Gender?

Your male partner’s sperm determines the gender of your baby. Each of his sperm has either male or female traits, and the one that reaches the egg first, decides which sex the baby will become. In other words, if a sperm containing male chromosomes reaches the egg first, a baby boy will be born. If the sperm that contains female chromosomes reaches the egg first, a girl will be born.

Gender Swaying

If you are dead-set on trying for a particular sex, you can incorporate a few gender swaying techniques. First, you will need to establish the time of possible conception by charting when you are most likely to ovulate, and then determining which days would be most optimal to have sex in order to conceive the gender you want. This is known as the Shettles Method. The principle behind this method is quite simple:

Although male-producing sperm, or Y-sperm, swim faster than female-producing sperm, or X-sperm, they do not live as long. In addition, the acidic level of the vagina is more alkaline closer to ovulation – in which Y-sperm flourish.

Since boy sperm swim faster, they tend to get to the egg quicker than girl sperm do. If you are trying to have a boy, you will need to have sex on the day of ovulation or one day before. Do not have sex for several days leading up to ovulation, as this will decrease your chances for a boy. You will want to make sure that the egg is there to meet the sperm as boy sperm do not live as long as female sperm.

To conceive a daughter, you should have intercourse two to three days prior to ovulation. This will allow for plenty of time for the boy-producing sperm to die off before you ovulate; therefore, it will only be female-producing sperm that will reach the egg.

However, another popular method of gender swaying, known as the Shelan Method, actually encourages the opposite of the Shettles Method. With this method, it is believed that having sex four to six days before ovulating will increase the likelihood of fertilization by male-producing sperm; while having sex two to three days prior to ovulating will produce a girl.


If you are unsure when you ovulate, you can chart your basal body temperature, as well as use an ovulation prediction kit that can help you pin point the day of ovulation.

According to Fertility Authority, there are many methods that can help you to conceive either a boy or a girl. But the only legal, FDA approved method for gender selection in the United States is pre-implantation genetic screening (PGS); when it is used along with in vitro fertilization (IVF) it almost 100 percent accurate.