Ditto to the above...but the wives tales that I have heard are...

Boy sperm swim faster but die quicker

Girl sperm swim slower and die slower.

I don't know if that is true so technically if you want a girl, DTD 2 days before "o", but if you want a boy DTD as close to..

For me, as long as I have one little bub at the end of all this is enough for me.