Mumsnet user Ironriver said she wanted her nine-year-old to do a sport such as football or rugby instead.
“Lots of the boys do football so I would like him to do that,” she wrote on 28 November.
“I’m showing him how cool football, rugby and karate is but he’s having none of it. He does modelling... I don’t think ballet is going to fit in. Any ideas?”
The mother was met with comments from parents calling her “sexist” and saying she should let her son do what he wants.
”Your poor child, having such a sexist mother,” one person wrote. “Let him do ballet, let him do what he wants.”
Another person wrote: “Let him do the thing he is interested in and actually wants to do. It’s 2016! Boys don’t just play football. Just like not all girls do ballet.”
One mum commented: “Thank your lucky stars he wants to do something athletic.
“What about all the mothers out there wringing their hands because their sons won’t put down the video game controllers and get off the couch?”
After receiving negative responses, the original poster agreed that her post came across “bad”.
“I didn’t mean that boys can’t do ballet,” she wrote. “I’m not saying ballet is bad, I just don’t think it’s going to help his career, as lots of the boys do sports, so to keep up his chance, he should do something like that.”
But many weren’t satisfied with her response.
“How would ballet have any effect at all on his career?” one person replied. “I don’t see what his career has to do with it?
“Anyway, surely better he does a sport he’s interested in, no point trying to force him into a sport he doesn’t want to do.”
Another wrote: “He’s nine, for pity’s sake. He’s a child. This is the time to try new things and make mistakes and get your hands dirty and have experiences.”