What hereditary effect, if any, does alcohol have upon the nervous system? As the temperance movement gained popularity and political influence in the 19th century, the potential influence of intemperate habits on human heredity became a pressing topic for concern in both the medical and the religious press. The shared anxieties of medical and religious institutions led to an abundance of pamphlets and treatises that attempted to unite the religious and phrenological views on the dangers of intoxication. In this paper, I argue that by examining the significance of phrenological thought to the temperance movement, we can better understand how ideas of the transmission of illnesses and vices from parent to offspring were diffused in the 19th century to the reading public. Drawing on John van Wyhe’s characterisation of phrenology as a popular medium through which scientific naturalism gained prominence, I show that the temperance movement provided a site of discourse that communicated not only the dangers of alcohol, but also theories of reproduction, heredity, and the transmission of acquired traits. As such, the temperance movement prioritised some understandings of the laws of heredity while overlooking or downplaying others.