  Gender imbalance is a well-known phenomenon observed throughout sciences
which is particularly severe in software development and Free/Open Source
Software communities. Little is know yet about the geography of this phenomenon
in particular when considering large scales for both its time and space
dimensions. We contribute to fill this gap with a longitudinal study of the
population of contributors to publicly available software source code. We
analyze the development history of 160 million software projects for a total of
2.2 billion commits contributed by 43 million distinct authors over a period of
50 years. We classify author names by gender using name frequencies and author
geographical locations using heuristics based on email addresses and time
zones. We study the evolution over time of contributions to public code by
gender and by world region. For the world overall, we confirm previous findings
about the low but steadily increasing ratio of contributions by female authors.
When breaking down by world regions we find that the long-term growth of female
participation is a worldwide phenomenon. We also observe a decrease in the
ratio of female participation during the COVID-19 pandemic, suggesting that
women's ability to contribute to public code has been more hindered than that
of men.
