So dd is 3 and ds is 1. They adore each other at the moment. But as my mum utters darkly, so did my brother and I at that age. But we had a horrible sibling relationship for my whole childhood and though it is ok as adults we have totally different personalities and ways of doing things. That's fine - we are different people, but I really want my kids to love and support each other, as kids but as adults too. I knew there will be teasing etc, but my brother used to really dislike me, and walk out of a room if I walked in etc. I genuinely did not deserve this - my presence rather than my behaviour was what annoyed him. On reflection he was always painfully shy and I was always confident and chatty. Ironically he married someone like me and my husband is also quite quiet, and we all get on with each other's spouses superficially at least, I am not sure if we'd all be friends if we met independently.
Anyway my question is this - what can I do now with my kids so young to try ensure this doesn't happen to them and that they are best friends, or at least not enemies?