This article analyzes how scientific thinking evolved in Argentina during the 1820s and 1830s. I will focus on liberals’ association of science with the emergence of a new male sensibility that feminized the role of men in society. This gendered scientific culture explains how liberals clashed in the 1830s with the policies of the governor of Buenos Aires, Juan Manuel de Rosas, whose hyper masculinist model based on the authority of the father was perceived not only as anti-civilization, but also (...) as anti-science. This association of gender and science helps us to explain how the introduction of Darwinian ideas that seemed to support a more masculinist representation of evolution, now ruled by laws of survival and competition, was perceived as a contradiction of past ideas by the 1870s. (shrink)