Mrs Princhester and I have an interest in this topic. There are a few books about a theory or theories about how you can do this. The one at hand suggests that male zygotes swim faster, die younger and that by playing about with timing and tight underwear etc you can influence outcomes.
The book claims to be based on “the latest scientific research” but it has (at least to me) the faintest whiff of pseudoscience about it.
What say you? Valid or vacuous?
Do it standing up in the wardrobe. You’ll have a boy.
I’ve developed a secret technique that guarantees a 50% rate of success.
Skammer, my point precisely. What I find tres unconvincing about the book we have is its inclusion of breathless testimonials from readers for whom the technique has “worked”, but no survey of readers to show that they haven’t selected merely the 50% for whom it no doubt does.
However, I’m interested in whether there actually is any scientific evidence to back the theory propounded.
We are about to undertake the same step, and so I too am interested in this topic, so I took a little look around on the web. I assume that you are talking about Shettles theories, which are either very effective or not at all effective, depending on who you bbelieve.
From WebMD:
“There’s no real evidence to show that they work,” says Sandra Ann Carson, MD, president of the American Society for Reproductive Medicine, noting that such techniques are as effective as random sex in producing a baby of the preferred sex."
The same article references a review of medical literature by J. Martin Young, MD, who says that following Shettles methods actually lowers your chance of choosing the sex of your child from 50% to 39%. (actually, you have a 51% of having a girl and 49% chance of having a boy, all other things being equal).
According to Young:
“If you would like to have a female, you would schedule intercourse to be as close to the time of ovulation as possible,” says Young. “If you would like to have a male child, you would have intercourse a number of days before to try to increase the probability.”
The success rate for this strategy of choosing the sex of your child, says Young, can be as high as two chances in three (about 67%), if done properly."
Who’s right? Who knows. Good luck, though.
People have tried to change the gender of their baby by, for instance, dressing a boy child in girls clothes and leaving his hair long… but the results are mixed.
According to this page, smoking increases your chances of having a girl; however the difference is marginal. This madsci.org page mentions a similar study, though the figures are different. (Note: IANAD but even I know smoking while pregnant is stupid.)
The missus and I are expecting and some Asian ladies she works with made a prediction on the gender using the “Chinese Birth Calendar.” They claimed to have accurately predicted the sex of every baby born to an employee of the company, except one, over the past seven or eight years. A quick survey at my workplace showed it to be right 17 times, wrong 2 times.
If it is that good of a predictor, then I suppose it could be used as a planning tool. It is based on the mother’s age and the month of conception.
“Darling shall we retire to the bedroom?”
“Not this month dear, afterall we want a little girl.”
I think you’ll find that the artificial insemination/IVF-based methods are more reliable. Do a Google search on baby sex selection and go from there.
With that sucsess rate they might qualify for James Randi’s challenge. It might be difficult to test but if you can it’s an easy 1 000 000$.
Unless the age of the mothers and sex is closely linked.