Transgender activists are resorting to threats and intimidation in an attempt to silence opponents.

Christian Today reports a Professor has been verbally and physically threatened for defending the necessity of confirming biological sex as opposed to self-identification for transgender.

Professor Rosa Freedman wrote, '[We] are being demonised, harassed, and targeted for expressing opinions based on the expertise for which we were hired and for why we are revered.”

Her office was vandalised with urine on the door and she was followed on campus, forcing her to hide behind a tree.

“These kinds of intimidation tactics are cowardly and disappointing,” said Binary spokeswoman Kirralie Smith. “The merits of transgenderism need to be academically and scientifically researched, analysed and debated without the threats, harassment or intimidation. This does nothing to further the cause of radical gender activists.”