One of the biggest café chains has said its stores can ban children from consuming caffeine.
Costa Coffee say their staff now have the discretion whether to serve certain drinks to the under 16s.
The move follows supermarket chains banning the sale of energy drinks, which typically contain high levels of caffeine, to school-age children.
Costa is the UKs largest chain, with 40% of the UK coffee shop market.
It has more than 1,500 branches on high streets, garage forecourts and motorway service stations and a further 900 overseas.
Some cafes have reportedly started challenging those who look under 16 and have refused to serve them drinks.
One father told the Bristol Post his 12-year-old daughter was turned down at the Costa Coffee cafe in Conwy, Wales, this weekend when she ordered an iced coffee.
I had never heard of Costa doing this before, her older sister has often bought her own drinks at Costa before, he said.
This is as an occasional treat rather than regular coffee drinking and a lot of Costa drinks do seem to be aimed at younger people.
He said he wished there was a blanket policy across all stores to avoid confusion.
He added: If they are concerned about health then perhaps they should they also stop selling cakes or high calorie drinks to overweight children because obesity is a far more serious health issue in this country than caffeine consumption.
A Costa spokesperson told Metro.co.uk: We do not encourage the sale of caffeine to children under 16 and it is at store discretion to question a customers age if they have any concerns.
Our advertising is not directed at children and you must be 16 or above to own a Costa Club Card.
Caffeine information is available upon request should a customer wish to know the level of caffeine in their favourite Costa coffee.
Earlier this year, Costas owner Whitbread announced they were selling the firm to American giant Coca-Cola in an astonishing £3.9 billion deal.