How big is your family?
How many people are there in your family?
How many brothers and sisters do you have?
Do you have any brothers or sisters?
I'm the oldest/the youngest/the middle child/an only child.
My parents were not expecting to have me, they told me I was "an accident".
We are expecting a new addition to our family in May.
I come from a big family. My parents had ten children.
I have five sisters and three brothers.
A: Are you married?
B: Well, no. Why do you ask?
A: I thought I saw you with your son yesterday having lunch.
B: Oh, that wasn't my son. That was my nephew. My sister's boy. She also has a daughter.
A: If you don't mind me asking, why don't you get married?
B: Well, I think that's kind of a personal question. Maybe I haven't met the right guy yet, or maybe I'm comfortable being single.