Natural law is not moral law. There are many natural laws. It takes a male and female to reproduce is one. I do believe our moral law is also a natural law. Now you need to learn that natural laws have changed since creation. They have been changed by God at least three times.
1) When man sinned, nature changed to include a "cursed ground", by God.
Genesis 3:17 “Cursed is the ground because of you;
through painful toil you will eat food from it
all the days of your life.
18 It will produce thorns and thistles for you,
Romans 8:19 For the creation waits in eager expectation for the children of God to be revealed. 20 For the creation was subjected to frustration, not by its own choice, but by the will of the one who subjected it, in hope 21 that[h] the creation itself will be liberated from its bondage to decay and brought into the freedom and glory of the children of God.
2) Flood, God said you could eat meat, the sky/atmosphere changed such that rainbows appeared. This resulted in people living much shorter lives.
3) Tower of Babel, the one race became many with multiple languages.
You acknowledge our moral law to be a natural law. How one responds to nakedness is part of our morality, moral law. Scripture is quite clear that how man responds to nakedness changed after sinning. Therefore man's moral law was changed at sinning. It is quite simple when you think it through.
I quoted scripture that says God cursed the earth. Explain to me how man eating fruit directly caused thorns to appear.