This paper brings together the study of transnational flows in global health and the gendering of technological artefacts. It does so through a case study of vaginal microbicides for HIV prevention, which have commonly been advocated for as a tool for women’s empowerment in parts of the world where HIV is most prevalent, namely sub-Saharan Africa. Drawing on fieldwork in the UK and Zambia, I argue that there is nothing inherently gendered about this ‘woman-controlled’ technology. Combining the notions of scripting and ‘making things public’, I demonstrate the political nature of transnational technology design and testing in the field of sexual health. Rather than framing this in terms of ethical debates, as is frequently the case in studies about the ‘global South’, I ground the analysis in the scripting and de-scripting of technologies and users. By focusing on how things are made public in HIV prevention, I draw attention to the normative, transformative and political potentials of new technologies, such as microbicides, and discuss the implications for their therapeutic success.