The paper focuses on the phenomenon of 'clean joke' Web sites. Such sites are often described as providing family-friendly humor, which is safe for children. However, our analysis reveals that the term 'clean joke' has mainly one operative meaning: a joke which is 'sex-free'. Whereas sex is excluded from 'clean joke' sites, sexist, racist and ageist content does appear in them. Therefore, the problematic message some of these Web sites convey is that: a) sex is 'dirty'; and b) sexism and other forms of discrimination are 'clean'. We interpret these findings both at the cultural level as manifestations of negative Western attitudes towards sexuality, and also at the technological level as easy solutions for child protection in the digital era.