(Did you know that some women have still gotten pregnant despite having a sterilisation! That must be awkward!)
Sorry for the slight off-topic, but I just wanted to throw out there that vasectomies are not 100% failproof/permanent, either. I have a good friend whose father had a vasectomy and 10 years later, his wife got pregnant (and yes, the baby was his.)
So yeah...I know it is extremely rare, but I will be forever paranoid now and even if my husband had a vasectomy, we would probably still use some other form of BC.