I had the pleasure to meet Joan Friedman at the Multiple Births Canada conference this past September. I had spoken with her a few times over the last few years about twin dynamics, raising twins and limit setting. Joan is an expert on twins and one of her main messages is to reinforce the importance of seeing multiple birth children as unique individuals.
For the folks that I see raising multiples or who are themselves adult twins the messages in families - never mind society - play a huge role in individual development and self-actualization. The story you are told about yourself from birth plays a huge part in how you have relationships, how your organize yourself in the world and how you see opportunities or limits.