Can alleged sex-offenders legally sue their accusers for defamation?

Answer 1

if person made a mistake and lied then yes but if is true and happend then no but I feel people innocent and falsely accused and convicted should be able to clear there name and people who done it and guilty should get there organs cut off and get death penalty and before they do to get raped and molested also as punishment.so they know how it feels when they done it to children and woman etc.

Answer 2

If the person making the accusation is knowingly lying and the accusation is false, then yes.

There's more to defamation laws than that single point, and there are exceptions, but that's the general rule.