Children need to learn that they do not automatically get presents just because the brother/sister has a birthday. Yes, it's hard to explain that to a toddler, but once they are big enough to understand, it's not hard to say "This is Sister's birthday. Remember when you had your birthday? That was when you got presents, and Sister didn't get any." Or else "When it's your birthday, then it will be your turn for presents."
Otherwise you fall into the trap of "everything must be equal for the children's entire childhood." Nobody can be recognized for anything special. If Sister brings home an all A+ report card and Brother brings home a sprinkling of C and D, they both get a celebratory pizza party, and so on.