Quoting Rabbit™:" Um, you know this is in Abortion Survivors right? The only thing I know about gender swaying is that ... [snip!] ... for boy) but you can alter your vaginal pH to be more hospitable to x or y bearing sperm (depending on which you want)"
I've read this as well, but I don't know how accurate it is.
Apparently if you orgasm before him, then you are more hospitable for a boy. If he orgasms first, then girl.
Like I said, I don't know if it works. We have a boy and I always orgasm 2-3 times each time we have sex (before him).