I was asked recently about my thoughts so I figured I'd share.
I didn't mind being an only child. Sure, I asked for a sibling periodically but it never was a hang-up.
We didn't live near extended family so my parents and my friends at school were my support system. Being an outgoing kid erased any loneliness I felt. We moved from one small community to the next, so similar backgrounds and shared separation/new school/new friends issues bonded me quickly to my peers. In that regard I was lucky.
As an only child, I was fine.
It was once I graduated college that I realized I'm alone. Should something happen to my parents, I'm the only one left. It falls to me to check up on them (they may find that a silly thought, afterall isn't it their job to check up on me?). If I want to pull off a surprise for them.. it's my secret to keep. I have no siblings to share childhood stories with. My kids have no aunts, uncles, or cousins. Though my husband has one brother, he's not married, has no kids and they are estranged anyhow. I have no one to call up and gab to. My mom is great, but she'll always be Mom, you know? So here I am, 8000 miles away (granted, by choice) with a single tie to the United States and home.
Of course I don't feel that anything is lacking in my day to day life for it's always been like this. It's just a little lonely when I'm asked about it or when I stop to think about it. As a kid, parents do everything for you, give you so much, and often there are best friends who substitute for siblings. Once you become an adult much of that changes or disappears entirely. I know that our lifestyle then and our lifestyle now magnify the feelings of separation and solitude. I'm not saying my parents have cut me loose. Far from it. They are still as involved in our lives as ever and I love them for that.
It wasn't through anyone's fault or choice that our little family stayed the way it was. We all would have loved to welcome a new person, but it wasn't meant to be. I feel blessed to have four children of my own who will always be there for each other when when their father and I are gone, and for that I am truly thankful.