After watching "Predestination (2014)", I could understand that:
Jane, John & their orphaned baby were the same person; -- played by the actress Sarah Snook
the barkeeper, Agent Doe & their older self "fizzle bomber" were also the same person; -- played by the actor Ethan Hawke
But by showing the operation scars on the agent Doe's body, it was revealed that even:
the heroine (first set of 3) & the hero (second set of 3) were also the same person!
No plausible explanation was given for that plot twist.
How can they turn out to be the same!?