This is true. I am a middle born and that is kinda true about me. same for my bro another middle born. and my oldersister first born. the only one that is wrong is my little sister "last born" she isn't like that really.
When teaching history, I used to try to explain this to students- usually with little success. People have a hard time grasping how many people it took to make them. and how that gives us huge family trees. ** This is very interesting.