Actually Adam was created by crossbreeding a Chimp and an Alien. (Annunaki). Sumerians have tablets depicting Adam as the 1st test tube baby.

Eve was then created by putting Adam into a deep sleep. (Anesthetic). By removing a rib from Adam, the Annunaki was able to extract bone marrow and create Eve. The first women that was able to have babies.

As the 1st woman wasn't able to reproduce because with hybrids (cross breeding) they cannot have kids. Such as a mule (Cross between donkey and horse).

After they were told that they are now able to have children, but the downside is the "great pain" etc etc.