This Is a Man’s World? Changes in Disposable Income Predict Sex Ratio at Birth

Ohto Kanninen, Labour Institute for Economic Research, Finland
Aleksi Karhula, University of Turku

The human sex ratio at birth (SRB) is long known to be relatively constant globally at around 107 boys born for every 100 girls. However, SRB has been rising until the World War II and declining after it in most industrial countries. Recent studies have shown that SRB varies according to exposure to chemicals and socioeconomic conditions. Here we show that changes in disposable income are positively associated with SRB in OECD countries. This is the first evidence to show that economic and social conditions influence SRB even at the macro level. This open up the field for studying the effects of social forces on phenomena that are traditionally considered to be entirely biologically determined.