At what age will doctors agree to giving a vasectomy?

I've asked my doc for the snip. I've got two gorgeous boys and me and the wife don't want any more kids, but the doc says that I should wait until I'm a bit older in case we change our minds or we split up. I'm 32 and feel that I've done my bit for furthering our species and don't want any 'accidents' in the future. How old to I have to be? Surely, it's my body to do with what I please isn't it?