There are
two creation stories in the Bible. In one story God creates man and woman right away. In the other story Adam was created first. I don't think it's meant as androgynous. Adam is a man because he feels incomplete without Eve.
No,
sex was not the original sin. God actually wanted them to have sex and children. First sin was distrust in God's benevolence - what if God doesn't want us to become like Him? At first sexual desire was good and pure but after eating the fruit of knowledge of good and evil they began to have dirty thoughts and shame (looking at naked bodies). That's why they wanted to be covered...
The mythological story has nothing to do with any hidden scientific truths. You are ascribing a meaning only you invented.
Once I started a thread about hidden meaning in the Bible:
Interpretation: "hidden" meaning - intended or invented?