Is there a natural way to influence whether you are going to conceive an anatomically male or female baby? Sex determination boils down to some X’s and Y’s. Females genetically present with two X chromosomes, males have one X and one Y chromosome. During conception, many factors affect the pairing, however the end result on the baby’s sex is ultimately determined by the sperm. Women only carry X chromosomes, so every baby has at least one X chromosome. But each sperm has either an X or a Y chromosome and the sperm that penetrates the mother's egg first will pair with the X chromosome, and create a male (XY) or female (XX) zygote that will grow into a little human.
Some believe that you can use timing of the cycle to manipulate the pairing process and influence the outcome. During a typical cycle a woman drops one egg from an ovary which waits in the duct below to be fertilized by a sperm. The limited window of opportunity for fertilization to occur is about 12-24 hours. Most sperm only live for a maximum of five days after ejaculation. Typically a sperm with the female (X) chromosome is bigger, moves slower and lives longer than a sperm with the male (Y) chromosomes. In the 1960’s Dr. Landrum B. Shettles suggested use of this knowledge may shift the odds of a particular sex type one way or the other. For example, if attempting to conceive a female the strategy is to time your intercourse a few days before ovulation so most of the fast swimming, short-lived Y (male) chromosome sperm will have died off before the egg is released. On the flipside, if attempting to conceive a male baby, timing your intercourse just as the egg drops may increase the chances that the egg will be fertilized by the faster moving Y-chromosomes.
According to the Shettles Method the acidity of the vagina also plays a vital role in gender selection. Closer to the vaginal opening there is a higher acidic environment than there is deeper in the vagina. Therefore, the fast swimming, weaker, male (Y) chromosome sperm are more likely to survive if deeper penetration is used during intercourse, Shettles mentions “doggy style.” The deeper location of ejaculation puts the male sperm closer to the site of implantation, and in a more alkaline or basic environment for survival. Positions such as “missionary” are recommended when attempting to conceive a female as they are resilient enough to survive the acidic environment that is closer to the opening of the vaginal canal. Vaginal potential Hydrogen, commonly referred to as pH, is also in a more alkaline range closer to ovulation which is optimal for male sperm. Female sperm benefit from the acidic environment days prior to ovulation, as the male sperm do not survive as easily.
The Shettles method has many fans and many critics, as some studiesdeny that sperm even swim at different rates. It does not at all guarantee success, however, some sources claim that following the Shettles protocol provides a success rate of 80-85% and the methods for a girl are a little less at 75-80%.