Does Adam and Eve's original sin have to do with sex?

Great question. Original sin has nothing to do with Adam and Eve having sex. 

God created them not only with the ability and freedom to have sex, but with the instruction to do so!... "So God created man in his own image, in the image of God he created him; male and female he created them. God blessed them and said to them, 'Be fruitful and increase in number...."

Have you ever read Genesis (first book in the Bible), chapter 2? It says in sentences (verses) 16 & 17: "the LORD God commanded the man, 'You are free to eat from any tree in the garden; but you must not eat from the tree of the knowledge of good and evil, for when you eat of it you will surely die.'"

Adam and Eve one day listened to Satan (disguised as a serpent) who lied to them and told them: "'You will not surely die,' the serpent said to the woman. 'For God knows that when you eat of it your eyes will be opened, and you will be like God, knowing good and evil.'"²

Satan told Adam and Eve a lie. He contradicted God's Word and said it was okay to eat from the forbidden tree.

The sin of Adam and Eve was disobeying God and doing what they wanted...instead of listening to God. They listened to Satan and their own reasoning, thinking God was keeping something wonderful from them, which He was not. And that's just like all of us. We think we know better than God. We think God is restricting us, keeping something from us, and we have a better way. 

Just like Adam and Eve, we are tempted to choose to believe Satan rather than believe God. Here it is: "When the woman saw that the fruit of the tree was good for food and pleasing to the eye, and also desirable for gaining wisdom, she took some and ate it. She also gave some to her husband, who was with her, and he ate it."³

From that moment they became spiritually separated from God -- He sent them out of the Garden of Eden, banned them from the tree of life, and instead of living forever, they eventually died. Death was not part of the Garden of Eden. The Bible says, "The penalty of sin is death." 

This is why Jesus came...to carry for us the penalty of our sin, so we would not die eternally separated from Him. When Jesus died on the cross, He fully paid for all of YOUR sin, and today offers you complete forgiveness and eternal life. The Bible says, "The penalty of sin is death, but the free gift of God is eternal life in Christ Jesus our Lord."⁴

Gaudin Mission International