A father's hilarious letter to his daughter's school about sexist activities has gone viral.

A father’s angry letter to the principal of his daughter’s school has gone viral after he shared it on Twitter.

NSW father Stephen Callaghan wrote the letter after learning that his 12 year-old daughter Ruby had time-travelled back to the 1960s. Or at least that’s what the activities the school was forcing the students to do made it feel like.

I wrote a letter pic.twitter.com/oFJp7egVnf

— Grumplestiltskin (@2FBS) December 6, 2017

“I must draw your attention to a serious incident. When Ruby left for school yesterday it was 2017 but when she returned home in the afternoon she was from 1968,” he wrote.

“I know this to be the case as Ruby informed me that the ‘girls’ in Year 6 would be attending the school library to get their hair and make-up done on Monday afternoon while the ‘boys’ are going to Bunnings.”

He insisted the principal “search the school buildings for a rip in the space-time continuum? Perhaps there is a faulty Flux Capacitor hidden away in the girls’ toilet block?”.

Listen: Do you have to stay for the whole school concert? Post continues after audio.

“I look forward to this being rectified and my daughter and other girls at the school being returned to this this millennium where school activities are not divided sharply along gender lines,” he concluded.

The activities in question were due to take place for the school’s “Year 6 Boy’s and Girl’s day” on Monday before their graduation.

The girls are to be treated to “fabulous hair and light make-up” while “the boys will not be left out, going to Bunnings, activities and a BBQ lunch,” according to the newsletter announcement.

Callaghan told news.com.au that his daughter was “affronted” she wasn’t given the choice and “very indignant” that only the boys were afforded the option of going to Bunnings, however she was keen to get her hair done.

He said he aimed to make a serious point with his humorous letter that women still bear the brunt of “thoughtless sexism”.

Parents were quick to share their own similar experiences on Twitter.

Yeah, they do this crap at my kid’s holiday care thing. The boys have ‘unbelievably amazing adventure day’ (I’m paraphrasing) and meanwhile the girls have ‘makeover day’.

— Jamie Q Roberts (@Jamieqroberts) December 6, 2017

My kids also had colouring-in sheets handed out once during a rained in lunch period with princesses and superheroes. Naturally they pulled the teacher up on their error very politely — as expected for girls (though inwardly truly exasperated!). https://t.co/PXDfCzL7vr

— Tasmin Waby (@TravellingTaz) December 6, 2017

I’d much prefer Bunnings!

I had to fight to do maths enrichment instead of grooming and deportment classes when I was at school. I was the only girl in that class ????

— Röbïnä (@RubyandAlex) December 6, 2017

A Department of Education spokesperson told news.com.au that while no parents had yet raised their concerns with the school, they would be accommodating any student who wanted to do the alternative activity.

Has your child’s school ever done something similar? How did you respond?