"The boys, for 'flipz n trix', tend to do more free running," Shaw told Fairfax.
"The girls tend to like to do some of that and then also some bar and some beam; that's the coaches' feedback."
Marchant told Fairfax her daughter wanted to do gymnastics with her friends.
She found the explanation unreasonable.
"The only reason I can think of is she's a girl. I just hate the way that would have made her feel and the message that's giving her. It's not good."
"She wants to do flips and tricks; that appeals to her," Marchant told Fairfax.
"They did say she'd be on the floor at the same time as her friends, but I thought, imagine that for her, she'll [have to say] 'I'm over here [because] I'm not allowed to be over there."
Marchant said her daughter was upset about not being allowed to join the boys' class.
"She wasn't crying or anything but I think it just further accentuates what she sees all the time, when she's trying to fun about with her mates. I think she considers herself not quite equal. As a girl you're just a little bit down the rung so she has to work harder," Marchant told Fairfax.
"When she was a little kid I made her a book of 'girls doing awesome sports things' just so she can see that imagery."
Shaw said the gym offered mixed-gender classes and had holiday programmes where boys and girls took part together.
Shaw told Fairfax it would be "very, very difficult" to include her in the boys' classes.
"We found the boys' requirements differ for this age group to the girls, and we could not safely combine them successfully."
