New categories not appearing on home page

I have tried to add new categories, that contain new posts, but they do not appear on my home page. They show up in the drop down menu, however.

The new categories contain several posts. What I’ve noticed is that my new category will appear if it contains at least one old post, but will disappear if that old post is deleted. New categories, with only brand new posts, will not show up on my home page… just the drop down menu. How can I get a new category, with only new posts in it, to appear on my home page?

I have the Aperture Theme with the latest WordPress update.