While Michael Jackson himself admitted that there was no real Billie Jean , the Billie Jean in the song represented girls that had earned their duplicitous 15 minutes of fame by chivying his brothers .
The man and the woman danced together, and he considered himself lucky to be her ‘chosen one’, to be the one whom she chose to ‘love’ (or at least that was what it seemed like to him at that time, when he was na?ve and fell for her tricks) . His actions gave his male friends the impression that they had consummated what she led him to believe was their love. He was completely awestruck by her for a while. Then he shed his naive skin , and got to see the real deal ; he finally got to see who she really was, and what she really wanted from him, and what their ‘relationship’, as she called it, really meant. Then he called off their relationship. And the woman was overcome with anger because no man had ever dumped her before; it was her who all the dumping earlier on. So she takes revenge on him by getting impregnated (possibly by some other man, and deliberately, too), and now he has to try to clarify to his male friends that he was lying; he never really did have sex with the girl, but hey, who is going to believe him given the picture they’ve been painting of themselves? Everyone’s going to believe the girl, no matter how rotten she may supposedly be, and they’ll point the finger at him for getting her pregnant with his child. The ultimate message here could also be that one should be careful of one’s company and should not trust just anybody with their secrets .
In the song, the woman sends him photos of her baby, claiming it to be his (as matched by the eyes), but he keeps insisting that it isn’t his . He says that the law might be on her side, but at the end of the day, he has just one thing to say : the woman, Billie jean, was not his girl, she never was, she is just someone who claims that he is the one that she had a relationship with, and the same man whose child she gave birth to; it is his love child , but the kid is not his son.
Although there are many stories surrounding the identity of the real Billie Jean, some people say that she was a huge fan of Michael Jackson and she claimed that her child was his. Jackson denied it, and it was later proved that the child was, indeed not his, and the woman was later sent to a mental institution. The song seems to indicate that he wasn’t in denial (because some interpretations lead to the belief that he did have a child with her), and that he truly had nothing to do with the woman’s kid, and that he was completely sure wasn’t his kid. Jackson himself clarified it, that Billie Jean wasn’t any single girl in particular , and nor was the song about him . It was just about groupies who wanted the world to think that they had kids with them.