Different.

One has blond hair; the other has brown.

One wears glasses; the other does not.

One knew his alphabet by the age of 2 1/2; the other just says A-B-C.

One could watch TV all day; the other would rather run up and down the hall.

One likes to play outside sometimes; the other could LIVE outside. 

One has brown eyes; the other has hazel.

One would pass up a cupcake at birthday party for a plate of fruit;

the other wouldn't dare.