why I was born as an only child?

I think parents should have more children, this is very frustrating when I'm doing things I enjoy and all of a sudden my parents came and told me to help them do something that i do not want to do or because I do not want to leave the activity I was doing. If I had a brother, surely they would call my brother to do it, unfortunately I do not have one. I think, I do not want to be born as an only child in my family. Sometimes, I think maybe I have a brother or sister. I have many friends of girls and boys, and almost all are in the family's youngest child. I always think how happy they have a brothers or sisters.