Almost 15,000 children have been expelled or suspended from school for sexual misconduct in the past five years - some even as young as four.
In East Sussex, two five-year-olds were sent home after sex assaults on other pupils. Other offences included indecent exposure and sexual assault.
Nick Seaton, secretary of the Campaign for Real Education, blamed the figures on an increasing sexualisation of young people.
"This is a serious issue needs addressing," he told the Huffington Post UK. "The shocking figures are a reflection on some of the explicit sex education given to young children. They are being sexualised at such a young age.
"Both Channel 4 and the BBC's sex education videos show children are far too adult. These sorts of things undoubtedly have a negative impact on our children."
The BBC has previously come under fire for its films, which include information on masturbating and "wet dreams".
Education secretary Michael Gove recently stirred up controversy after he told the education select committee "clever children had safer sex".