That hasn't happened to me, and I was an only. However, back in the 60s and 70s when I was a kid, I definitely got the feeling that being an only was uncool. Mum was furious because people said she had to adopt if she couldn't have more kids of her own. Otherwise, they said, there was a danger that I'd turn out to be a problem kid in some way.
I suppose I proved them all wrong, since I did well in school, never did drugs or got into any trouble. Other kids accepted the fact that I didn't have siblings. It was just the older folks that looked at me suspiciously until they got to know me.
