To answer your question - NO. Any woman could become competitive if she trained and dieted properly. PERIOD.
Tatyana - awesome example.
Me - I did it.
And I do recall having the pleasure of working with Valentina Chepiga who was the reigning Ms Olympia at the time. She told me personally that she didn't begin to lift till she was in her late 20's and she was told that she would NEVER be able to make the necessary changes to her phyique to become competitive - EVER. That she was too old and her genetics were wrong. She was also bottom heavy (as was I). I guess she showed them. eh?
Also from back in the day - Ms Rachel McClish had a genetically inferior bone structure as in she was narrow shoulders/broad hips (like me too) and yet all these years later is there a women on the board who does not know her name?
NEVER EVER accept the *genetics* excuse. I am not saying that you will ever become Ms Olympia. What I am saying is that IF you really want to take your physique to a level that you never thought possible - you will most likely be shocked as to what you CAN DO once you get educated and keep trying till you find exactly what works FOR YOU.
*steps off soapbox*