A few things recently have made me wonder about this.
A mum I know has twin girls in different classes at the school (Year 1). Mostly they get invited places together as the children share friends, but the Mum was telling me that if only one of them is invited to a party then they don't go, as it causes too much upset.
Also twins in my DS's class. He likes one and plays really well with him. Wants him round for a playdate. The other one is rude and disruptive and teases my younger DS. I'd rather not invite him. Another Mum invited 'nicer' twin to play and was told by their mum 'oh, you'll have to have them both!'
Is it me, or is this all a bit weird? Don't parents of twins try to develop their separate personalities/ friendships etc?