When did Adam & Eve have sexual relations?

Did Adam and Eve have sexual relations while in the Garden of Eden, or after?

In Genesis 1 we read:

Gen. 1:27 God created man in His own image, in the image of God He created him; male and female He created them.
Gen. 1:28 God blessed them; and God said to them, “Be fruitful and multiply, and fill the earth, and subdue it; and rule over the fish of the sea and over the birds of the sky and over every living thing that moves on the earth.”

Later in Genesis 2, the Lord elaborated on this moment from Genesis 1:

Gen. 2:22 The Lord God fashioned into a woman the rib which He had taken from the man, and brought her to the man.
Gen. 2:23 The man said,
   “This is now bone of my bones,
   And flesh of my flesh;
   She shall be called Woman,
   Because she was taken out of Man.”
Gen. 2:24 For this reason a man shall leave his father and his mother, and be joined to his wife; and they shall become one flesh.

Finally, the Lord provided details of how they began a family in Genesis 4:

Gen. 4:1 Now the man had relations with his wife Eve, and she conceived and gave birth to Cain, and she said, “I have gotten a manchild with the help of the Lord.”

Based on these passages, we can say for sure that Adam and Eve had relations and conceived following the Garden, but we can’t be as clear on what happened prior to the Fall.

There is an implication in Genesis 2 that Adam and Eve had relations in the Garden prior to the Fall. Specifically, Genesis 2:24 says that in a marriage (like the formed with Adam and Woman) a man and woman shall be “joined,” which is a reference to sexual relations. This detail suggests – but doesn’t prove – that Adam and Woman engaged in such relations while in the Garden immediately after Woman was introduced to Adam.

On the other hand, this reference may refer only to Woman’s origin, and therefore we can only say definitively that the couple engaged in sexual relations after the Fall.