Romans: Rejecting God, Embracing Sin

Paul concludes that rejecting the glory of God as revealed in creation results in sexual deviation - homosexuality. How does this process work? Is Paul's conclusion warranted? And why, from the litany of sins that he lists that accompany, does he focus on the sin of homosexuality? In quick summary, God is the only reason to restrain sin. Once God is ignored (or "re-cast" to be palatable to sinful man) there is no restraint, and the inevitable result is a society bent on selfishness. The mark of such a society is homosexual sin.