1. Your standard for whether sexyism or any other form of discrimination is permissible begs the question. You say we need to ask whether the discrimination has a “degrading effect” on humanity, but that’s the very question of the topic: is sexyism degrading and therefore immoral? I have attempted a standard, albeit one that is not rigorously proven, for when employment discrimination is okay, while you have simply restated the question in different terms.

2. While I concede that I have not deductively proven the two essential elements of pernicious discrimination, I think the burden is really on you to disprove it rather than for me to prove it. Clearly we have an intuition that racism and sexism are immoral but that discrimination on the basis of actual talent is valid. What features, then, seem to distinguish the two? I submit that irrelevance and immutability constitute the difference, and I am yet to be convinced otherwise.

And no, that’s not “intellectual gymnastics”–it’s a transcendental argument. See http://en.wikipedia.org/wiki/Transcendental_arguments.