To be born again is to recieve the Spirit and live in it. It's to overcome the psychological discord brought about by the ego, and it's called being born again because you 're-learn' your ethics.

My assumption would be that being born again is for the definitively sinful, those ignorant to God and slaves of sin. But I have never considered myself a slave of sin. I have always loved my fellow human being and always cared about the rest of the human race as an instinct.