Is it possible that a man could be the father of your child if?

he has had a vasectomy, I've heard that it is. And does anyone know about anywhere cheap to get a dna test, possibly one that uses hair or something so that one of the potential fathers will not know that I am doing this. The other possibility is his brother(we were seperated at the time), I do not recall having any relations with my husband that month I conceived. yet, I did get pregnant, and his brother had the vasectomy. So I just want to know if anyone knows how I might be able to find out the answer with little expense and no knowledge of my attempts by either party. I don't wanna start no trouble, just wanna know for my own peace of mind, and so you know, the affair was no secret, my husband just said it was his child after of course saying he wasn't several times. I do not want to hear from any of you who wanna bad mouth me, if you haven't got anything nice to say, then don't say anything at all please.