my husband just had a vasectomy three weeks ago. with the way the dr did his, there is no way that i could get pregnant later. the dr cut a short section of vas out and therefore it is not connected to anything to transport the sperm. it basically just boils down to how its done and how good the dr is. in our case, getting it done didnt really make a difference in us not having anymore children. we found out 10 days after he had it done that i was pregnant. so he ended up having it done a few days too late. oh, well. the dr told us that after 15 ejacs (which could take up to three months) he shoudl be completely infertile. after 15, he has to go get a sperm count done, and when that comes back at zero, hes good to go.