One surgeon says to the other, "What do you specialise in?"
The other surgeon says, "Appendixes. It's quite simple: a little snip here, a little snip there and Bob's your uncle." He then says, "What do you specialise in?"
The other surgeon says, "Sex changes. It's not quite the same but it's still simple: a little snip here, a little snip there and Bob's your Auntie."