So when Shakespeare wrote (from one of the witches) ...
... "Thou shalt (be)get kings, though thou be none" ...
... he was just being a total butt kissing brown noser.
"Oh, look, Your Majesty ... a character in my play, speaking to Your Majesty's ancestor, predicted Your Majesty's reign ... mwah, mwah, mwah ... kiss, kiss, kiss ..."
There you go JJ, sorry to bring things back to land - but it looks as if Lady M was married before and has a non-Macbeth child.
http://www.jstor.org/pss/3206576
The wikipedia analysis of her character is quite interesting reading!
Last time I was in Daunt Books in Marylebone (last week) there was a Biography about Macbeth ... supposedly showing how different he was from the way that Shakespeare had portrayed him (rather like Richard III, I suppose).
Shakespeare when you are grown up is soooo different from the learning at school - I learned rafts of Julius Caesar when I was 12, had no idea what it was all about. The programme finishing the other day about two schools coming together for Romeo & Juliet was really good, youngsters who wouldn't dream of admitting to liking Shakespeare having a great time in a modern version. Brilliantly staged.