Abstract
This paper seeks to contribute to the knowledge of sex ratios at birth, their long-term evolution, and their de-
terminants, on a sound documentary base of almost one million records between 1550 and 1890. The region
studied likewise offers the advantage of being industrialised at the end of the observation period, which allows
relevant conclusions to be drawn about the effect of modern economic growth on family decisions regarding
their offspring. The main conclusions include the preference for males in the rural world, favoured by the
inheritance regime and the scarce ecclesiastical regulation in this territory, while the city levels were similar to
those of other European cities. From the 18th century onwards, a stability around the reference values in all
areas could be observed and which was only broken by the economic and social changes during industrialisation