I wouldn't overthink it, if both you and your partner want another, and you can afford to do so, then go for it. I am another who circumstance has dictated that I will only have one, and I am very sad about that. Mr Oi is one of four, and I am very close to my sister, and have very fond memories of our childhood together. One of the things that makes me sad is that Miss Oi will never enjoy sharing a hotel room with a sibling when on holiday and Be Able To Watch Anything You Like On TV Without Reference To Parents. Looking ahead, I am glad that when difficult decisions will have to be made with regard to my mum (my dad died a while back), who is in her 70s, my sister and I will have each other for support. The main thing I am doing is ensuring that Miss Oi and her cousin (also an only child, a year older) see each other as much as possible, and hopefully will remain close friends.