One notable case, hmm, in that case, every job field is filled with notable sexual harrasement cases and it's clearly a disadvantage to be a woman in any field, ladies should've just stay home and do housekeeping... wait then there's the cases of abusive husband and crazy serial killers.
Anyway, I know it's frustrating when you see others with less skill get paid better, just b/c they know the right person. But it doesnt mean you should say things like people get paid because they sleep with others. It's just wrong. You should think of it from the other point of view too, if you are an AD, who would you hire? You will be receiving tons of portfolio to review everyday, when you have three or ten artists with same skill level, which one would you be more likely to hire, the person you know, or a complete stranger?
Everyone has to start somewhere, instead of complaining, do something about it. Go out there and show them your art and convince them you are the better choice. Opportunities don't come to you, you have to knock on doors to get it.