interesting, hedra… I never knew that. My guess is that since fertility doesn’t seem to be a problem in my family, no one ever got a pH test.
Go to the link I posted above. There are two methods that use that theory, except that they arrive at opposite conclusions.
The Shettles method (aka what flodnak posted): have sex as close as possible to ovulation if a boy is what you want. If you try to conceive two to four days before you ovulate, you’ll most likely have a girl. (reasoning: Y-chromosomes have a shorter lifespan.)
The Whelan method (aka what vanilla posted): if you want a boy, have intercourse four to six days before your basal body temperature goes up. If you want a girl, abstain from sex until two to three days before ovulation. (reasoning: biochemical changes that may favor male-producing sperm early in a woman’s cycle.)
jayron 32: Assuming that we’re taking the number of cousins as fixed (16), and that boys and girls are equally likely by chance, then there’s a 2.1% chance of getting 4 or fewer girls OR 4 or fewer boys. This means that it’s going to happen one time in fifty even if there’s no real cause, but it’s enough to be considered statistically significant: The usual cutoff is about 5%. I include either gender and the “or fewer” clauses because you’d consider it just as remarkable if you had that few boys, or if the numbers were even more skewed.
There is something called the Shettles method that has to do with timing intercourse to conceive a boy or girl. Basically, you try after ovulation for a boy, before. ovulation for a girl from what I understand. It supposedly works better for trying for boys.
http://www.babycenter.com/refcap/2915.html is a quick overview.
–tygre