If the Snake had not told Eve to eat of the Tree of Knowledge of Good and Evil, would Adam and Eve have ever had any children?
Or would they still be tripping around the Garden to this day, living like brother and sister, immortal but alone?
God commanded Adam and Eve to populate the earth before they sinned. Having children is not a sin. I don't see any reason to think they would not have children if they didn't eat the fruit.
Genesis 1:28 God blessed them and said to them, "Be fruitful and increase in number; fill the earth and subdue it. Rule over the fish of the sea and the birds of the air and over every living creature that moves on the ground."
They were having children. God told them to go and multiply and they did that is where Cain found his wife. We don't know how long Adam and Eve were in the Garden, nor do we know why their children born in the Garden were not mentioned except when it came to Cain and his wife. That was God's plan so we would know that we were fallen and what happened after the fall. How would Eve know that she was cursed in child birth if she had never had a child any other way?