According to the theory of evolution, their greatest regret is incest for their children ... because there were only two humans in the world at that time. ...

Their descendants must be incestuous if they want to continue to reproduce. ...

The second regret is that both of them are orphans. They have never met their parents. ..

The third regret is that there is no marriage certificate ... because they have no witnesses and public ceremonies ... no one has a wedding reception ... so they just live together. ..

What's more, they didn't even remember the child's name.