This article, based on an analysis of English language medical literature on mumps' manifestation in men, women and children from the late eighteenth to the early twentieth century, examines the role of gender in shaping conceptualisations of mumps' severity and medical significance. Over time, gendered social roles undermined the medical notion of mumps as a severe disease of women while elevating mumps' reputation as a severe and significant disease of men, eventually casting the disease as a threat to masculinity. When the modern mumps vaccine was commercialised in the 1960s, its development built on a long history of gendered conceptualisations of mumps and its use cast children as safeguards of a legacy of masculine citizenship defined by military activity and fatherhood.