marjan - I feel like there must be other things that make you think this was discrimination because I don't really feel like not asking you to lunch is plain discrimination. Was it obvious that this was BECAUSE you're a woman? Do they do other things that make you feel like it's blatant disregard for your feelings?

And I understand that written english can be messed up when you are writing in anger. I am what you would call a grammar 'nazi' and sometimes I will post things while I'm upset and look at them later and go "oh my god I actually typed that"

This is a really tough situation. Are the higher ups the same? If so then going to the person or your boss wouldn't really do anything. Is there a section in your protocol or handbook or whatever that explains the correct route to take? That way you can make sure that YOU are doing the right things that way if any other actions need to be taken then you did the right things and they can't find any loop holes to get out of it.