just a note on the sex determination thing - i have researched the scientific literature quite extensively and both the vaginal environment theory and the "speed/longevity of sperm" theory have absolutely no peer reviewed evidence to support them, they are only theories - and with lots of holes in them! obviously some people find it works for them, but plenty of others have found it haven't worked! there are just so many millions of sperm that it really is the luck of the draw which one is successful.