Giving your toddler coffee?!?!

I guess I'm out of the loop on this controversy,I haven't heard much one way or the other ....I just noticed my friend on Facebook today had her 2 and a half year-old drinking a cuppa coffee with her this morning she claims it helps keep him calm or something like that...? I don't know I just remember when I was little my parents never would let me have coffee because they claimed it'll "stunt your growth"!!! Lol