Education Ordinance 1971 in Hong Kong not only provided girls with a much greater chance of receiving education than had hitherto been the case, it also had the effect of incorporating them into the regulatory framework of the school system. This paper examines how the discourses of civic education and sex education before and after reunification with mainland China have interchanged the concept of gender with the biological sex in the construction of the girl. In particular, it argues that, in the name of maintaining the stability of society, the developmental path for girls has been limited in the discourses of sex, personal and social education. As a result, girls are only presumed to become women and take up their appropriate gender roles according to the social norms of contemporary Hong Kong.[Copyright of Sex Education is the property of Routledge. Full article may be available at the publisher's website: http://dx.doi.org/10.1080/14681811.2011.627737]