If you look at the idea BC mentioned about the natural man (id) being the enemy of God in Freudian terms, it would lead you to the conclusion that the superego is the holy portion of the human psyche. However, it seems that these to sides merely obscess about sex differently. The id wants sex and the superego wishes to repress sex, but attention to sex is still at the forefront.
Stray thought: Could this repressive attitude toward sex have solved the problem of polygamy?
And let's not forget that "happiness is the purpose and design of our existence".
I think what most of you are forgetting is that LDS doctrine is that "the natural man is an enemy to God". These God given desires and abilities are to be used within the bounds the Lord has set. That is what distinguishes us from the animals. We exercise self-control and become Gods thereby. I don't think very many people would agree that the abode of the Gods is like the monkey house at the zoo.
But Joseph Smith used the argument above to modify those bounds so far outside what he had taught as to cause reasonable questions about whether God was really telling him to do so or not.