How big is your family?
How many people are there in your family?
How many 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.