An Aussie family has opened up about their journey to acceptance with transgender daughter, Emma.

Emma, now 12, was born Ronan but her mother Megan said they knew their then-son was different from a very early age.

Speaking to 60 Minutes , she revealed Emma will be put on puberty blockers, followed by hormone replacement therapy and then eventually sex reassignment surgery should she wish to have it.

“She's been extremely worried about her Adam's apple. Obviously, nothing's changed whatsoever but, in her head, it's that obvious fear that, 'Oh,my god, I'm turning into a man!'” Mrs Hayes said.

Megan says the journey began when she caught Ronan, then recognised as a boy, trying to cut off his penis with a knife at just 4 years old.

“I found her in the room just with a knife and pants down, and she tried to cut off her own penis,' Mrs Hayes said. [She] wanted to cut it off. She just didn't want it there. She didn't think it belonged there. She only ended up with a little scratch."

Emma was diagnosed with gender dysphoria at 8.