How to ask and answer to the question about someone's birth order in his/her family
I want to know
1- how to get information about what is the birth order of someone according to their siblings?
2- is there several ways to ask and answer to the questions about this issue?

Question

How to ask and answer to the question about someone's birth order in his/her family
I want to know
1- how to get information about what is the birth order of someone according to their siblings? 
2- is there several ways to ask and answer to the questions about   this issue?

Answer

I normally ask how many siblings do you have, what number are you. Birth order is important to me because I am a middle child and we have different mindsets then the first child or baby of the family.

Answer

In the US at least, birth order isn't that important.
However, if you are already talking about families, you can ask "Are you the oldest?"  Or "Are you the baby of the family?"  And the person will likely give you the answer that you're looking for.  If they don't, don't press - that would be very, very, very strange.