Human and lizard chromosome types and numbers don't match anyway so I guess no irresponsible breeding occurred here … and she was sentient and gave her consent too so it technically went around the only real ethical issue against bestiality, so….
Just to clear the confusion in the comments.
They had sex (human x lizard) not (human x human), and as we learnt today lizards insert diagonally compared to our more direct insertion. So that paired with them both being virgins(human x human) it’s safe to assume they were in over their heads