I guess I should have said "the sperm carrying the Y chromosome" and "the sperm carrying the X chromosome" instead of "the male sperm" and "the female sperm." (Of course, all sperm come from the man.)
The male sperm swim fastest and die fast, the female sperm swim slower but live longer. The theory on timing the sex for a particular gender is that IF you know when the woman ovulates (a hard thing to know at the best of times), to try for a boy you can have sex no earlier than the day of ovulation, since the males would get to the egg before the females. As you can see, this would require your wife to be using ovulation test kits and you'd have to be very careful not to have sex until the kit says ovulation is imminent. What the heck, it works for some people. LOL
There isnt really a way to guarantee a boy, but it is the sperm that decides the sex of the baby...womens' eggs are always going to be X but mens' sperm carry either X or Y :)
good luck anywho x
I don't think there are any ways that can guarantee it will be a boy however check out this site it gives some interesting information:
http://www.babyhopes.com/articles/how-to-conceive-a-boy.html