Originally Posted by oregon2010
Interesting. We weren't trying for either sex. But if you have sex 2 days before O and then again on O, wouldn't there be sperm already waiting? And having sex further away from O would seem to lower the chance of getting pregnant. I, too miscarried and DTD on day O so our chances were higher. It seems, according to those statistics, I am more likely to have a boy this time after a girl.
Yes, if you have sex 2 days before O and then again on O, there COULD be sperm already waiting, but it depends on how well they fare in the environment. So, if you have an acidic "environment" that favors x sperm (or rather, kills off y sperm), then if you had sex 2 days before O and then NOT on O, then the x sperm would be waiting, assuming they survived. But, if you had sex also on O, the x could still get there first for sure. Conversely, if you had a basic environment that favors y sperm, then the y sperm could be waiting, and get there first. Or, if the sperm just don't do well at all in the environment, they could all be dead by the time of O, and just the sex on O day is what matters.. This is why none of it is fool-proof and just changes the odds a little bit! People trying for a girl tend to either have a cutoff at 3 (or 2) days before ovulation, and NO BD after that, OR they try this O+12 hours theory, which says to abstain until 12 hours after you ovulate, which according to one theory gives a better chance of a girl. Who knows!!
And yes, ultimately, people who try for cutoffs and all that to conceive a girl do probably have a lower likelihood of getting pregnant, just because it is harder to catch that egg!
Basically, you are kindof always just slightly more likely to have a boy, just based on statistics, due to the natural occurring sex ratio in the population! Crazy!