OK…Right after you have sex, do a 7-minute headstand, wear pink socks, sing Katy Perry songs, and make sure your core body temperate is exactly 98.7 degrees. This will guarantee you to have the perfect little girl you want!
JUST KIDDING!
The gender of your baby is determined by which kind of sperm fertilizes an egg. A single sperm either carries the genetic material that leads to a boy or a girl. Each ejaculation leads to the release of millions and millions of microscopic sperm that try to find their way to the egg. Thus, you have about a 50/50 chance of having one or the other.
The idea that you can naturally control your baby’s sex comes from a theory developed by Dr. Landrum B. Shettles. The basis for the Shettles method starts with the fact that X-chromosome sperm (female) are on average slightly larger and thus slower moving than Y-chromosome sperm (male). And X-chromosome sperm live longer. So, according to the theory, if a woman can predict with confidence the day she will ovulate or release an egg, then have sex 3 or 4 days beforehand and not again until well after ovulation, there is a higher likelihood of producing a female child. This is because the longer living female sperm may still be hanging around 3 to 4 days later.
However, evidenced based medical trials have not been able to prove that the Shettles method works. And those that follow this method strictly may have trouble reproducing because of the lack of intercourse near ovulation.
So personally, I would not overdo it with trying to practice the Shettles method. I encourage couples trying to conceive to have sex either on a daily basis or every other day throughout the timeframe that should encompass their ovulation. Basically, relax and have fun!