A.P.
Sorry to confirm this...but no method of birth control (with the exception of abstinence) is 100% effective. A vasectomy is about as close as you can get, but it still has the ability in rare cases to reverse itself. The human body can do strange things. My little sister is living proof of a vasectomy that reversed itself...7 years after my dad had it done!!! To be safe, get a pregnancy test!