This can go under the category of "Things you don't really want said about your child" or "Things you never want to hear."
However, I did say this to my friend a while back and I meant it in the nicest way possible. I was honestly impressed with her swiftness and speed - that little thing could have her pants off in 2 seconds flat - pretty impressive for a then-2 year old. My friend, who is pretty quick-witted, just smiled and said something like "Yeah, she can be naked before you finish a sentence. I'm so proud."
You gotta love your parent-friends!