Catherine McGregor, who is the highest ranking transgender female military official in the world, was asked to appear on the program to discuss Australia's decision to become militarily involved in Iraq for a second time, as well as contemporary ideas of masculinity and femininity.

Her views were welcomed by the studio audience and those following along on social media, but towards the latter end of the show, two tweets flashed up on the screen which were seen by many to be in poor taste.

"Wow, he/she is a hero #QandA," tweeted @geoffgcooper.

"God sets our agenda, we shouldn't interfere #qanda," tweeted @secadvisers, before the same user deleted the account after an apparent backlash.

Immediately after the tweets went to air, a choir of Twitter users called on the ABC to issue an apology for the 'transphobic" and degrading comments.

An ABC spokesperson defended the tweets and said the ABC believed there was nothing wrong with them.

"We believe the tweets you identify meet those guidelines and were appropriate for broadcast.

"Q&A's on-screen tweets are selected through a multistage moderation process to provide an alternative layer around the studio discussion based on the commentary of viewers on Twitter.

"The tweets are chosen to reflect the diverse range of opinions in the Q&A audience.

"They are not expected to always be in agreement with the views of the panelists, but are expected to fall within our guidelines."

Lieutenant-Colonel McGregor, who was named in The Australian Woman's Weekly's list of Australia's 50 most powerful women, told News Corporation she wasn't overly offended by the tweets.

"I've had far worse things said about me online and I have been overwhelmingly well received,"she said.

"It's the nature of the show and it's the nature of social media.

"I've got a range of opinions and I respect other people's right to their opinions. I'm reasonably thick-skinned."