Y.C.
To be honest and I hope I don't offend any body.
I may have done the same comment just because sometimes it look like, in my case I OFTEN have the opposite. My older is mocha skin, dark eyes and hair, my younger is white, brown eyes and kind of redish hair (no idea why) and people have ask me if the little O. is mine, I don't get offended (unless I see an under mean tone) because she doesn't look NOTHING like me.
Before I came to America I never felt that I have to be so careful when talking about people of dark skin.
In Mexico we don't feel like saying black is a bad thing, with exception of some ignorants. We call "Negrito" to my cousin because he is the darkes of all of us, and we say it with love and never as a look down.
When I came here O. day I was with my MIL and I say:
"The black lady xyz", I don't even remember what it was.
OMG, my MIL yield at me and told me I could have got her in trouble?!
I was shock, I said as a color of skin and nothing else.
All since then I have being more careful of what I say but not because I see nothing wrong but because I know that in here, probably more then any other country, this is some sensitive subject and like my mom say, where you go do what they told...or something like that. No meaning that you have to follow everything you are told, but to follow and respect their ideas, or not that you don't have to do what you are being told, ok,I am talking in circles now, you get my point, I hope, lol.
I don't think the boys got offended unless they could hear a tone of voice or an actitud follow the comment, that make it look like something bad.