Pupils as young as 14 are being offered access to free condoms and the morning-after pill at a Devon school.
The school said it consulted parents beforehand
Braunton Community College is part of a pilot scheme by the North Devon Primary Care Trust which aims to make sex education more accessible.
Pupils will only be able to access the services if they have been through a sex education programme, called Apause.
Several parents have spoken out against the scheme, saying it will encourage sexual activity.
Apause, or Added Power and Understanding Through Sexual Education, will offer the morning-after pill, condoms and testing for sexually transmitted infections.
The Primary Care Trust said the aim was to reduce teenage pregnancies and sexual infections in a safer environment.
About 3% of girls under 18 in north Devon became pregnant between 2000 and 2003. Nearly half of them then had abortions.
Meanwhile, the rate of the sexually transmitted infection chlamydia in the area's teenagers rose by 60% between 2000 and 2004.
Dr Katherine Gronqvist of the Primary Care Trust said: "Young people can access these services from any family-planning clinic or from their GP, but their bringing on-site means we're providing support in a safer environment with better access than if they maybe have to take buses or travel."
The school said parents were thoroughly consulted beforehand.
Principal Viv Game added: "We also gave parents the opportunity to opt out if they would like. So every parent of every child who would be able to access this service has had the right to opt out even before it started."
But some parents opposed to the scheme said they were concerned the services were confidential, meaning they might not know if their daughter had been given medication such as the morning-after pill.
Those concerned are organising a public meeting next week to rally opposition.
Campaign organiser and father-of-eight Neville Wheelan, who would be affected if the scheme was extended to other schools, said the rights of parents and families were being undermined.
He said: "The consequences, psychological and physical damage that can be done is something that children should not be exposed to."