I'm the eldest and a pretty strong P...
We're like this:
me, 20, ENFP
younger sister, 18, ESFP
younger brother, 14, INFP
My brother is probably the most J out of all of us, but then not really by much.
My dad was an only child, ESTJ
Mother was in the middle of eight, ISFP (I couldn't begin to type her siblings)