Influencing Sex: Shettles Method & More - Truth or Bogus?

[Gokul43201]

This came up in a discussion I was having with a cousin of mine (who's going to have a baby soon). She said that the time of conception influences the sex of the baby, and gave me the following link :

http://www.childbirth.org/articles/sex.html

It sounded kinda dubious to me, so I bring it to you. Is there any truth to this ?

SUMMARY OF SHETTLES METHODS

Basically, men produce two types of sperms, the X (female) and Y (male). According to Dr. Shettles' studies the y-sperms are smaller, weaker, but faster than their siblings x-sperms, which are bigger, stronger, but slower.

Based on this fact, there are several things you can do to "favor" the conception of boys or girls:

(1) The most important aspect of all is timing of intercourse during the monthly cycle. The closer to ovulation you have sex, the better the chances to have a boy, because the y-sperms are faster and tend to get to the egg first. If you have sex 3 days or more before ovulation, the better your chances to conceive a girl, because the weaker y-sperms tend to die sooner and the x-sperms will be available in greater quantity whenever the egg is released. On the other hand, having sex from 2 days before ovulation, through a few days after ovulation, is better for conceiving a boy. Around the 2-day point -- 48 hours before ovulation -- seems to be the 50/50 mark.

Some other factors mentioned are pH, sperm count and temperature. I know that temperature influences the sex of amphibian offspring, but hadn't heard of any studies on humans.

So what's the verdict : bogus or not ?

 

[Kerrie]

I have heard this tends to be true, although not a science. as for the pH of the woman's uterine, i think this has an effect on which sperm will survive better. i

 

[DocToxyn]

While some of these techniques may work under anecdotal reporting, they most likely would not hold up under a more rigorous scientific approach. Check this article for a review.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9651654&dopt=Abstract

Much of the stated technique is probably based on the differences between sperm containing an X or Y chromosome. It has been attempted to sort, by centrifugation, sperm into two groups and they select the one, i.e., gender that you want. This physical difference probably lends itself to the "stronger, bigger female" and the "weaker, smaller male". A more technical and effective sorting can be done using flow cytometry and nuclear staining, but the safety of this is questionable and is currently only used for livestock, see Beltville method.

Temperature most likely deals less with the activities of sperm in the female and more with the male side of sperm production. A cooler than body temperature environment is best for sperm production, hence the placement of the testes outside the body (and we all wear boxers when trying to conceive right guys?)

 

[Gokul43201]

I was unable to read anything more than the abstract of that paper, not being a member and all. But thanks for the link and explanation, nevertheless.

If you can point me to a full article, I'd appreciate that.

 

[DocToxyn]

Sorry, I'll send you a private message with a copy of the article as a .pdf when I get back in the lab.

 

[Moonbear]

Pssst...Gokul...you do have access to that journal article. Look up the journal under the OhioLink Electronic Journal Center: http://journals.ohiolink.edu/cgi-bin/sciserv.pl?collection=journals

As for the methods described, even if they worked, most people aren't that good at predicting the precise date of ovulation well enough to make it at all practical. Seems like a good way to take a long time getting pregnant to restrict intercourse to one day of the cycle, especially if you're trying to aim for 3 days before ovulation. That's really pushing the limit of how long sperm survive considering it still takes some time for the ovum to move far enough down the Fallopian tube to be fertilizable. You wouldn't want fertilization to occur too high up in the Fallopian tube and risk a tubal pregnancy. Most people trying to achieve pregnancy will think it more important to have intercourse every day around the week of ovulation to maximize their chances of getting pregnant at all.

 

[Gokul43201]

Thanks Kerrie, Doc and Moonbear, for your responses. Most grateful.