I have often wondered over the years if I, the third, was actually adopted. I was the "brainiac", my sibs--let's just say, not scholars. My brother, the first born, said he was traumatized by my Mother going to work. Maybe I was too and just didn't realize it! My sister was a slob, and I've always been neat. My Dad, used to my sister's messy homes, asked me on a visit if my apartment was always so neat.
I do know that by the time I came along, 7 years after my sister, my parents had definitely loosened up. Then again, I never gave them reason to worry. No boy chasing, no joyriding, etc