I read this in regards to the Shettles system - I think I'd rather try for a boy! There's no way I'd be giving up my orgasms!
btw, found on BB's own website

Orgasm

For a boy, the woman should try to achieve orgasm either before or at the same time as her partner – or if you are lucky enough, multiple female orgasms can help! The theory on this is that the waves of the orgasm help to draw up the sperm quicker to the egg, again the boys getting a head start on the girls.

For a girl, Shettles recommends women avoid orgasm.