A school has banned a pupil from growing a moustache for a charity campaign because it says it is not an "inclusive" activity.
Gus Hooker, 13, from Dunstable, Bedfordshire, wanted to take part in Movember, where men grow facial hair to raise money for Prostate Cancer UK.
The Priory Academy said it was "not an activity that many children would be able to join in with".
The schoolboy said he thought he could have raised "a fair bit" of money.
Gus Hooker started shaving when he was aged nine and has to do it every day.
He wanted to take part in the campaign, because his grandfather recently beat cancer.
"Because I can grow a moustache, I reckon that if I did it I could raise a fair bit," he said.
"I just wanted to show off my moustache, everyone wanted me to go for it."
However, his father Paul Hooker said the teenager was refused permission because he would look "different".
Mr Hooker said he was told his son was one of only a few pupils of his age with facial hair and the others would be unable to take part.
He took to his blog to point out that there was nothing in the school's uniform policy about moustaches and that some of the staff were growing one for the charity campaign.
A spokesperson for the school said it could only support fundraising activities that are "entirely inclusive".
"Fundraising is an inclusive activity with all pupils having the opportunity to participate regardless of age or gender," a statement said.
"In a coeducational school with young children, growing facial hair would not be an activity that many children would be able to join in with.
"Whilst the school dress code does not explicitly mention facial hair, it does mention unusual hair styles and colouring that are contrary to a smart uniform appearance."
As a compromise, the school has allowed the teenager to organise a charity dress down day on 30 November, in which students will be allowed to wear fake moustaches for a £1 donation.