Did Adam and Eve have sex before the fall?
The Bible doesn't explicitly say they do, but there's a lot we can point to that heavily imply that it's incredibly unlikely they didn't.
Genesis 2:21-25
21 So the Lord God caused the man to fall into a deep sleep; and while he was sleeping, he took one of the man’s ribs[a] and then closed up the place with flesh. 22 Then the Lord God made a woman from the rib[b] he had taken out of the man, and he brought her to the man.
23 The man said,
“This is now bone of my bones
and flesh of my flesh;
she shall be called ‘woman,’
for she was taken out of man.”
24 That is why a man leaves his father and mother and is united to his wife, and they become one flesh.
25 Adam and his wife were both naked, and they felt no shame.
Part of Biblical marriage is the part in verse 24, "they become one flesh." Sex is a very important part of marriage and is the physical representation of a man and his wife becoming one.
Genesis 1:27-28
27 So God created mankind in his own image, in the image of God he created them; male and female he created them. 28 God blessed them and said to them, “Be fruitful and increase in number; fill the earth and subdue it. Rule over the fish in the sea and the birds in the sky and over every living creature that moves on the ground.”
This is before the fall. Increasing in number for humans requires married couples to have sex.
Genesis 3:16
16 To the woman he said, “I will make your pains in childbearing very severe; with painful labor you will give birth to children. Your desire will be for your husband, and he will rule over you.”
This is after the fall, but the way it's stated implies giving birth to children was a preexisting concept. The difference between before the fall and after isn't sex, it's shame. Sex isn't inherently sinful, it becomes sinful when taken out of it's intended purpose.
