Funny, when God pronounced the curse on Adam and Eve, He said that Eve’s conception would greatly increase. IOW, before the fall, most of sex would NOT have been for the purpose of having children.
HMMMmmm…
Genesis 3:16
To the woman he said,
“I will surely multiply your pain in childbearing;
in pain you shall bring forth children.
Your desire shall be contrary to your husband,
but he shall rule over you.”