This article examines letters written by young men to the Marathi-language journal Samaj Swasthya and its editor, R. D. Karve, a major advocate of birth control and sex education in western India. The letters, and Karve's responses to them, constituted perhaps the earliest sex-advice column in Indian print media. We argue here that the correspondence provides a unique vehicle for understanding the forms of sexual knowledge held by middle-class males in mid-twentieth-century India as well as for appreciating their most significant sexual anxieties. The article analyses the concerns expressed in the letters about masturbation and seminal emissions, the nature of the female body and processes of conception, birth control and same-sex sexual practices. It particularly illuminates the ways in which the concept of modern conjugality pervaded the sexual understandings of the young men who wrote to Karve. It thus offers valuable insights into specifically sexual aspects of conjugality and masculinity—aspects that have previously been unexplored.