Preheat oven to 350 degree F (175 degrees C).
Sift together flour, baking soda, baking powder, salt, and cinnamon.
Stir the chocolate chips into the dry ingredients.
In a large bowl, cream sugar and butter or margarine.
Beat the egg slightly, and mix into the creamed mixture with the bananas.
Mix in sifted ingredients until just combined. Stir in the vanilla. Add milk one tablespoon at a time, making sure the batter does not become too moist.
Pour batter into a greased and floured 9x5 inch loaf pan.
Bake until top is brown and cracks along the top (about 55 minutes). After about 30 minutes, cover with a tented piece of aluminum foil. A toothpick stuck into a crack in the top should come out clean.