Because I was an only child. My cousins (three kids in the family - two boys and a girl) thought I had it made - I had reasonably well off parents, I got “all” the Christmas presents, “all” the birthday present - woo! Me? I found it a lonely existence. My parents didn’t love one another - as my mother put it, “We were the last two people we knew who weren’t married, so we got married” - and it showed. I was there to basically be a picture on the desk at work, give my father a kid to gripe about, and give my mother someone to gripe at, and that was it. I hated being an only child, and wanted a sibling - if for no other reason than to distract my parents from me for a while. Never happened, though.

Segue forward 37 years. When my wife and I got married I told her, “I do not want to raise an only child. We can either have none, or more than one”. Well, she was up for multiple kids, so we ended up with three of the best kids on the planet. (Sorry, folks - you may *think* your kids are the best but, really, ours are :-). So in my case being an only child convinced me I’d never want someone else to be an only child. And as it turned out, none of our kids are. :-)