Tuesday, February 16, 2010

Choosing Your Baby's Gender?

You've got a 50/50 chance of conceiving a boy or a girl, right? Your X-chromosome egg will either be fertilized by the Y-chromosome sperm and make a boy (XY) or an X-chromosome sperm and make a girl (XX). But what if you could influence the outcome?

Even though we'd love our baby no matter what gender, there are very few of us who wouldn't love to be able to choose whether we have a boy or girl.

Wives' tales and folklore abounds on how to influence the gender of your baby.  Here are just a few examples:

If you want a boy
- Eat more meat — the redder the better
- Make love standing up
- Make love on an odd day of the month
- Warm testicles and sperm
- Woman sleeps on the right left side of the bed

If you want a girl
- Give in to your chocolate craving
- Make love with the woman on top
- Make love when the moon is full
- Cool testicles and sperm
- Woman sleeps on the right side of the bed
- You put a wooden spoon under your bed and a pink ribbon under your pillow

Is it truly possible to choose your baby's gender?  (I'm referring to methods that do not involve sperm selection and in-vitro fertilization) Many people believe that yes, science shows us we can.

The Shettles Method is a popular method developed by Dr. Shettles, who based his methods around the belief that the X and Y sperm have different traits:

X-chromosome sperms are slower swimmers than Y's but survive better in cervical mucus. Y-chromosome sperms are faster but less hardy and survive for a shorter amount of time in cervical mucus.

Here is a summary of what he found in his study:

1. Timing:  The closer to ovulation you have sex, the better your chances of having a boy because the Y-sperms are faster and will get to the egg first.  Having sex 3 or more days before ovulation will give you a better chance of conceiving a girl because the weak Y-sperms will die and the X-sperms will still be hanging around when your egg is released. 
2. pH of a woman's vaginal tract: More acidic environments favor X-sperms. Y-sperms will be killed off. According to Dr. Shettles, women should try not to orgasm during sex if trying for a girl because it will make the environment more alkaline. When trying for a boy, both partners should try to orgasm at the same time.
3. Position of intercourse and Depth of penetration: Deep penetration places the sperm closer to the egg and the quick aggressive boy sperms will get a head start. Also, shallow penetration is a more acidic environment. Shettles recommends missionary position for a girl and rear-entry (doggy style) for a boy.
4. Sperm count: When trying for a boy, don't have sex for 3-4 days before you reach the target date (right before ovulation). For girls have sex every day until 3 days before ovulation. Men should wear loose underwear (switch to boxers!) to keep testicles cool for Y-sperms, although Shettles doesn't recommend the opposite when trying for girls.
5. Caffeine for the man right before sex to give Y-sperms a boost.

Is the Shettles Method scientifically sound?
There are numerous medical articles that examine why the Shettles Method is flawed and most medical studies have not been able to replicate the numbers that Shettles himself claims to have seen. In fact, some studies have shown that those using the Shettles Method may actually have trouble conceiving.
It seems pretty clear that many of the methods of trying for a girl, especially, would make it harder to conceive at all. The time closest to the actual period of ovulation is the time during which humans are most likely to conceive. It is incredibly hard to conceive at all - I remember learning in an Anthropology course that the human species has a very low probability of conception.  The Shettles Method recommends that if trying for a girl baby that you stop having intercourse at 3 days before ovulation, which makes you less likely to conceive overall! I also remember learning from a Psychology teacher (though this wasn't part of the curriculum, haha) that the best intercourse position to conceive in was doggy style - Shettles' recommendation for a boy!

Many women and their partners will say that it can't hurt to try the above methods, just in case they might work! They'll mark dates on their calendar to have sex, measure the pH of cervical mucus, withhold orgasm (gasp!) and so forth.  But is this just as fruitless as "putting a wooden spoon under your bed and a pink ribbon under your pillow"?

What do you think?


  1. Eh, I think I honestly wouldn't care about gender of my baby. What interests me is your last paragraph about the difficulty conceiving...

    So, I was reading recently about the Jewish laws of Nidda, which say a man and woman cannot be intimate while a woman is menstruating and for 7 clean days after that (for a minimum 12 days). Furthermore, men are not allowed to masturbate, so in those 12 days, there is little or no ejection of semen. Anyway, what I read is that besides all the psychological benefits such as growing your non-sexual relationship in that time, etc, there's also biological benefits. In fact, some OBs will even recommend similar practices. Why? Because during menstruation, there's no chance of the wife getting pregnant, right? So they use that time to boost the man's sperm count, so when the woman's finally "clean" and ovulating, they have a much higher chance of conception.

    Food for thought!

  2. You might care about gender if you had all 3 girls or all 3 boys and wanted one of the opposite sex! haha.

    You know whats crazy? I've heard that you -can- get pregnant if you have sex while menstruating (I guess if the sperm hang around in there for a bit? I'm not sure) which seems to be totally crazy based on the fact that I mentioned - that its really hard to conceive at all, especially outside of the fertile time of ovulation! Human bio is so weird :)

  3. What a great post! I bet mommies will ask you about baby's gender all the time;)


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