You want the what cake?

My son Elijah turns 5 on Wednesday and we were having a small party to celebrate. I take him to the bakery like I do every year to pick out a cake. You know, a football cake or baseball cake, or maybe a Cars cake or Hula Hawaiian cake like last year. So I show him the 20 or so cakes in the display case and his #1 pick is the snow white cake with a big figurine of snow white and a castle in the background. "You sure you want that cake son?" "Yes, I want the princess cake!" (The princess cake is absolutely not an option. Not just the gender role thing but the Disney marketing machine has tricked my son into thinking he wants 'princess cake'.) "Elijah, I'm sorry son, the 'princess' cake is sold out. What's your second pick?" "Oh, ummm, I'll take the baseball cake." "Oookkk, baseball cake it is!"
As I happily order the baseball cake I wonder: what is my fear with my son getting a princess cake? Am I training him to be sexist by limiting his options for expression? Answer to self: Oh well, at least he got to pick from the football or baseball cake. He'll get over it and I'm already over it.