I took the survey. Out of curiosity (too late to change now) what should I have answered if I'm not my father's first child, but I'm the first child he had with my mom? (There are kids from my dad's first marriage, but I didn't grow up with them).

I went with "no older siblings" since I assumed this was a question about socialization (or maybe even about uterine environment) but not siring. But I'd like to know for next year.