Do we know what causes lying?...promiscuity?...addiction?...selfishness? or positives like diligence?...honesty?...monogomy?... on and on and on we could go. All behavior is a combination of genetics, environment and choice. That is no excuse, however. When you steal, you still go to jail. When you lie and cheat, you still have no friends. And when you are sexually promiscuous or risky, you still reap the unhealthy rewards. Sadly, so does society as a whole when the behavior is normalized and accepted.
Well said, RAT Patrol.
Exactly. The problem with these "bio-robot" explanations is that they are designed with the purpose of giving people an excuse for bad behavior.
I think you're right on. However in this case it can be simplified. I'd submit that it's simply the need for love (both physical and emotional) and acceptance. You gotta admit... those are two very powerful drives in a human.