This video, which was posted at cbmw.org, is an excellent treatment of the relationship between the authority of Scripture and the authority of natural law, with a linkage to gender and sexual identity ethics. It's certainly not for the faint of mind, but I certainly commend it to anyone as a basic but extremely articulate overview of these topics. For the short of attention, feel free to start viewing at 22:00, where you'll find a succinct summary of the first 22 minutes before he begins to build the linkage relevant to gender and sexual identity. I hope you'll find it as encouraging as I did.
As I listened, I found myself frequently reflecting on Romans 1. Here Paul argues from natural law in Romans 1:18-20 that God's wrath against godlessness and unrighteousness is justified. He then illustrates a downward spiral into darkness, at the depths of which was the worship of manmade idols. But in Romans 1:24-25 he declares that the ultimate consummation of idolatry, the fundamental exchange of the truth of God for a lie, is sexual impurity. The Holy Spirit's drawing out of this theme, that the fundamental error in sexual impurity isn't that it is the violation of some arbitrary rule but that it is the most profound expression of idolatry, has been key in my own discipleship journey.
God doesn't want to spoil our fun by asking us to arbitrarily constrain our desires. Rather, He wants us to find expression of our eternal desire for Him in the temporal expression of sexual desire in a relationship that conforms to His creative intent.
