advice to help pick the sex of your not yet concieved baby

okey well i was watching the discovery channel this morning and there was this program on about delivery's and there was a section on there about all different ways of determining the sex of your baby ect ect and then there was this scientist or whatever that explained about how the boys sperms are the fastest swimmers and the girl sperms are the slow swimmers but live alot longer than the boy sperms as the boy sperms die not long after they get to the destination, anyway basicly if you have sex for a week before your egg is released (you ovulate) you will probably have a girl as they live long enough to wait until the egg is released then bam! there already waiting there so they fertalize the egg first, wereas if you wait until you are ovulateing for sure, its likely you will have a boy as they are the faster swimmers so they will deffinately get there first, also they said that if a woman orgasms before the partner does that also helps the boy sperms stay alive  (excresions ect help keep them alive ect) i hope this advice has been helpful and don't mind my spelling mistakes as i don't know were spell check is lol