With the article on the masculinization of births Population is launching
a new series of annual chronicles coordinated by Dominique Tabutin and
devoted to the state of world knowledge on a topical demographic issue.
Targeting a broad audience of scientists, students, journalists and more, these
chronicles will combine factual data with an overview of the theoretical and
political aspects of the question in hand. By approaching topical issues in
historical perspective, these articles will shed light on their wider context.
After a critical description of information sources and measurement tools, an
overview of recent research will describe ongoing trends and pinpoint social
and spatial disparities. A discussion section will then explore the political or
legal implications of the current and future situation, and the challenges facing
researchers. Statistical and methodological appendices may also be included.
The new series is inaugurated by Christophe Z. Guilmoto, who examines
the question of the sex ratio at birth, which in humans naturally stands at
around 105 boys per 100 girls. Scholars have long been interested in measuring
variations in this ratio at different times in history, and among different
populations or communities. The first accurate estimate was made by John
Graunt in 1661, who found a ratio of 106.8 boys per 100 girls among infants
christened in London. According to United Nations estimates, recent changes
in sex ratios in certain populous countries of the world, such as India and
China, have raised the global sex ratio from 105 in 1975-1979 to 108 in 2005-
2009 (World Population Prospects: The 2012 Revision). These recent increases
in the proportion of male births have been attributed to gender discrimination.
In this article, the author analyses the mechanisms and causes of this
phenomenon and discusses its social and political implications.