There is also hidden incest right in the beginning of the Bibble. When Abel and Cain sacrifices for God, God is pleased with Abel's sacrifice and not with Cain's. This as we know it lead Cain slaying Abel known as first murder.
The missing part is why Cain became so angry by losing to his brother Abel? In Islamic, Beta Israeli and Ethiopian Orthodox Church the tradition says both Abel and Cain were born with twin sisters Awan and Azura, and when Cain lost Adam decided Abel should marry Cain's twin which lead to first murder. While this sounds weird, it made perfectly sense to people at that time. In Babylonian mythology first Gods were Absu and Tiamat, who bore twins Lahamu and Lahmu, who bore twins Anshar and Kishar and they in turn bore the Elder Gods. Adam's decision broke this cycle, and this was the background story which was left out from our version of Bibble.