Eldest child

Reasons are: they had undivided attention from their parents, they were given more responsibilities than their siblings at an early age, they felt the pressure of greater expectations. There was a theory that adding a child diminishes the family’s "intellectual environment."

Einstein as first born

Relevant dynamics may also include the tendency of families to label each child: the family cut-up, the klutz, the whiner, the New York Times notes. Eldest children tend to be tagged the most responsible. When asked what parents should do about this, one psychologist answers: nothing. “Younger siblings are more likely to take chances,”

Oh dear! lol

I think this sums up my question (or the answer) pretty well.

cats and dogs

cat dominates dog