The only downsides I have heard of is if it doesn't work (rare), or when the male decides he wants to have another baby (usually this happens when he hooks up with someone younger who wants one). That is why a lot of doctors won't do it until you are older. At your age, I don't see any reason to NOT do it, and it is a lot better than sticking your wife on the pill, which would expose her to a lot of unnecessary potential side effects, not to mention a decrease in libido. Personally, I think all males should do this once they are sure they don't want children.
Relax... I'll need some information first. Just the basic facts - can you show me where it hurts?