The sexuality of women during fieldwork with men becomes constantly scrutinised, and sexualised, and the perceptions of others on our sexuality often impinge on sex research processes in patriarchal societies. This paper discusses challenges and conceptual reflections of gender interactions in sex research fieldwork by a woman with men aged 18–54 in Nairobi, Kenya. It also provides insights on practical safety strategies for women conducting sex research fieldwork. The paper draws on the researcher's field notes and reflections on experiences and interactions with gatekeepers and male participants to present brief accounts of challenges of gender interactions in sex research fieldwork. The impact of gender on the well-being of women doing gender interactions sex research during fieldwork in patriarchal societies is particularly salient. The scrutiny on women, women's sexual subjectivities and positioning of their sexuality by men occur more often than may occur with male researchers who research women. The reproduction of sex knowledge is a key aspect of ethical considerations and part of the ethical reproduction of knowledge, which needs to consider difficulties with gender interactions. Hence, this paper is a proposed resource for fieldwork and policy making in programmes that support the sexuality of men.