birth order and gender affects your upbringing directly.

A few things:

I've never had a sister and so I am tremendously motivated to want to have a daughter as a result
I don't have a sister so I am simply curious what that is like. It seems to not really matter
my perception due to previous relationships was exacerbated by my sibling's current relationships
my youngest sibling takes after me too much - he's like me on crack (the otaku part; i weeded it out of my system but he's gone full justy mode)