I just want to offer my children a choice. When I grew up my brother and I shared a room but we didn't have to, then I think when I was 10 either myself or my mum decided to have my own room and I loved it. I'd be happy for my children to share when they're younger, sharing a room with my brother was one of my fondest memories. But for studying, friends, own space for privacy I needed my own room as a teenager and I wouldn't want to deny my children that even if they were the same sex. If they choose to share a room- fine by me! DH shared a room with his brother who he has always gotten on with really well but he hated it, especially with there being 4 kids he never used to get his own space, we have been together since we were 17 but never stayed at his house (8 years on) he was embarrassed as a teenager and as a result we aren't as close to them as my family as James practically lived with us. Bit of an extreme example, I know lots of people are happy to share but I will want to be in a position to let the children decide not put up with what we have.