Hi there - well I don't have any experience, except to say yep, thats right, apparently girl sperm swim slower and live longer, and boy sperm swim fast but die quicker.

Personally, I kinda wonder about it...

And have always heard that it's not wise to put hope in having one sex over another (that said, would love a boy over a girl... but of course, I'm sure I'll be absolutely stoked with whatever happens to grow!).