I am going to start this in the religious section since it I simply dealing specifically with religious beliefs, however, Mods, if there is a section that is better suited, please feel free to move it there.
Now for the purposes of this particular discussion we are assuming a spontaneously created Adam with Eve having been made from his rib, per the Bible account. Anyone who cannot provide arguments within that context will be given nasty emojis and call a spoilsport and a party pooper.
After we assume our premise, we are left with the quandary of where the rest of us come from. Many people will say we are all descended of Adam and Eve, but few ever think of what that implied.
The first and immediate implication is that we are all distant products of incest. If Adam and Eve were the only people created, then their children would have been forced to have other children with their siblings, and maybe even with their parents. In this case, I use forced as in no other choice not as in against their will.
Our second option is that Adam and Eve were the prototypes and God then later spontaneously created other humans for their children to go out and have children with. The mentioning of other people first occurs when Cain is cursed for killing his brother, and he is worried that others will exact revenge beyond God's punishment, hence the mark from God to prevent that. Yet, after that passage, it is then revealed that Adam and Eve had Seth, noting specifically that they had himafter the loss of Able, and then had many more sons and daughters after Seth. So then where did the others whom Cain was afraid of come from. Eventually Cain found a village and married some one from it, but due to the lack of described time passing, and their multi centuries of life back then, there could have been a population build from any of the methods listed here.
Our final option also stems from the accounting that there were people for Cain to be afraid of and later marry. And that is simply that they evolved and form the main stock of humanity.
So which do you believe is the origin of man after Adam and Eve were created or if you don't believe in the spontaneously created Adam and Eve, which do you feel is the more likely under the assumptions of the thread? If you reject all three, and still remain under the assumptions, what is your theory?