As examples, good is separate from evil (attempts to blur their differences are known as moral relativism and are anathema to Judeo-Christian values); life is separate from death (in part a reaction to ancient Egypt, which blurred the distinction between life and death); God is separate from nature (see part XVI); humans are separate from animals (see part XV); and man is separate from woman. Blurring any of these distinctions is tampering with the order of the world as created by God and leads to chaos. So important is the notion of separation that the very word for "holy" in biblical Hebrew (kadosh) means "separate," "distinct."
This helps to explain one of the least known and most enigmatic laws of the Torah, the ban on wearing linen and wool together in the same piece of clothing (sha'atnez). Linen represents plant life, and wool represents animal life. The two are distinct realms in God's creation.
And that is why the Torah bans men from wearing women's clothing.
"God created the human being, male and female He created them" is how Genesis describes the creation of man and woman. Blurring that distinction is playing God, and doing so in a highly destructive manner.
If a man gets a sexual thrill out of wearing women's undergarments in the privacy of his bedroom, that is not society's concern. It may be his religion's concern, and, religious or not, it may be his female partner's concern (one wonders how many women married to cross dressing men are pleased by the sight of their man in a bra and panties). But it is not society's concern, which is why anyone who cares about protecting the right to privacy should have been horrified by the American news media's reporting about the private cross-dressing habits of a nationally known sportscaster.
However, when a man does this in public, he has publicly blurred the man-woman distinction, and society has the right -- and the duty, if it cares about Judeo-Christian values or simply cares about not confusing children as to sexual identity -- to say this violates a norm that society does not wish violated.
The war waged by cultural radicals at universities, in state legislatures and in courtrooms against the very distinction between male and female is one of their most significant attempts to undo the Judeo-Christian foundations of American and Western culture. And they know it. That's why fighting to blur gender distinctions is so important to them.
Now the rest of society needs to understand why not allowing that to happen is so important.