Whilst sex education in Australia has moved beyond a focus solely on abstinence, it is still in many instances shaped by what Silin refers to as the 'silences' that accompany topics considered unspeakable to young people. The present article focuses specifically on one such silence, namely the representation of non-heterosexual sexualities and non-gender-normative people in the context of sex education. By focusing on three South Australian websites that act as first ports of call in terms of information about sex and sex education to young people and their parents, the analysis provided suggests that two of the three websites evoke a range of heteronormative and gender-normative assumptions, with one of these sites more explicitly emphasising reproductive heterosex, and the other adopting a liberal approach that nonetheless fails to adequately challenge stereotypes about nonheterosexuality and non-gender normativity. The third site, by contrast, provides relatively progressive inclusion of a range of genders and sexualities, and addresses homophobia and its effects. The article concludes by suggesting that websites providing information about sex to young people and their parents must make a substantive shift away from perpetuating the silencing of marginal sexualities and genders, and towards contributing to open public discussion about young people and sex.