I have heard that I can help determine the gender of my baby. How can I do this?
You are probably thinking of the Shettles Method which is based on
the premise that sperm carrying the X and Y chromosomes have different characteristics
and that you can influence the reproductive environment to favor one or the
other. While there is some controversy surrounding both the credibility and
the morality of the method, here's how the theory goes:
It is the sperm that fertilizes the egg that will determine the sex of your
baby. Some sperm carry the X-chromosome and some sperm carry the Y-chromosome.
If an X-chromosome-carrying sperm fertilizes the egg, the baby will be a girl.
If a Y-chromosome-carrying sperm fertilizes the egg, the baby will be a boy.
The idea behind the Shettles Method of sex selection is based on the premise
that the X and Y chromosome carrying sperm have different characteristics and
that under different circumstances either X- or Y-chromosome-carrying sperm
will be more likely to fertilize the egg.
The Y-chromosome-carrying sperm are said to:
- be faster and smaller than the X-chromosome carrying sperm.
- die faster than the X-chromosome-carrying sperm.
The X-chromosome-carrying sperm are said to:
- be slower than the Y-chromosome carrying sperm.
- be better able to withstand the acidic cervical environment before fertile
cervical fluid is produced.
Based on these premises, according to Shettles, you can time intercourse, choose
a sexual position that favors conception of your preferred sex and influence
the reproductive environment to increase the likelihood of conceiving your preferred
sex. These are the suggestions from Dr. Shettles:
To Get A Boy (According to Shettles):
- Time intercourse as close to ovulation as possible: The idea is that since
the Y-chromosome sperm are faster than the X-chromosome sperm, there will
be more Y-chromosome sperm who reach the egg, making it more likely that a
Y-chromosome carrying sperm will fertilize the egg.
- Abstain from intercourse for four to five days prior to ovulation. Have
intercourse only just at the time of ovulation and just before.
- Have intercourse that allows for deep penetration. Shettles recommends rear-entry
(aka, “doggy-style”). The idea is that the sperm will be deposited
closer to the cervix where cervical fluid is most friendly to the Y-chromosome
sperm and where the “boy sperm” are more likely to survive since
there is less distance to travel.
- Men avoid tight clothes: heat kills off both types of sperm, but will kill
off the less protected, smaller Y-chromosome sperm faster, according to Shettles.
- Women have an orgasm: According to Shettles, female orgasm increases the
alkaline secretions in the vagina that are favorable to the Y-chromosome carrying
sperm. Shettles recommends having an orgasm before or at the same time as
the male partner.
To Get a Girl (According to Shettles):
- Have intercourse 2-3 days before ovulation and avoid intercourse just before
ovulation until 2 days after ovulation and when you have peak cervical fluid:
The idea is that when you have sex a few days before ovulation, only the X-chromosome
“girl sperm” will be left in the female reproductive tract waiting
to fertilize the egg when it is released.
- Have intercourse with shallow penetration: Shettles recommends “missionary
position”or any position that will deposit the sperm slightly away from
the cervix, giving advantage to the longer living, but slower X-chromosome-carrying
- Women avoid orgasm: Shettles suggests women avoid orgasm because it makes
the vaginal environment more alkaline, and less acidic and is disadvantageous
to the X-chromosome “girl sperm”.
If you are taking longer than expected to conceive, it is generally not recommended
to attempt any kind of sex selection as it can increase the time it takes to
See also: Review of scientific articles about intercourse timing and gender selection.