Why Do Men Have Nipples

So, I just had a pretty interesting coversation with Mark. Here is how it went:

Mark: You know what I was thinking?

Me: What?

Mark: Well I know, I know that you have to have certain body parts like, eyes, nose, mouth and ears, but . . . why do guys have nipples?

Me: (smirk) That's a really odd question

Mark: Well I know what women have them for and I know what everything else is used for but I was in the shower this morning and I looked down and thought 'Why do I have nipples'.

He was really really serious about this and I know it's going to bug him. He even asked me to look it up and figure out "Why Men Have Nipples". I want to say I may be afraid to know unless it is to find out that they can be used as some form of torture to make them take out the garbage. I do have to say though that a man would look pretty strange without them; sort of like a Ken Doll. That's enough to give me a nightmare or two.

It appears that Mark thinks best in the shower.