Dh and I very deliberately chose to have an only child. We are both from a family of 3 children, but do not feel that ds will be missing out.
Luckily ds is an uber-friendly, confident child, runs up to anyone and anything when we are out and "chats" to them. Perhaps it is because he is an only child that he is so friendly and trusting of adults, I don't know, I will never know.
I just know that his personality makes him an ideal candidate for being an only child, he will NEVER be lonely because he has loads of relatives and is so obvioulsy good at making friends.
I have had lots and lots of people ask why I have settled for an only child (dh and I are both 39, so it's defo. not late to have more) and they have usually followed it by something negative, like your ds will be lonely, etc.
I wish people weren't so judgemental, I would never dare question someone who has 10 kids or no kids. One of my best friends never married, never had kids, is now retired and living abroad and very very happy about it.
I am glad that people have bigger families, it will keep the human race going, but I am happy with one extremely beautiful and happy son