Sex ratio is the number of women to men within a population. With little to no outside interference, this ratio is naturally equal (or very close to equal) at 1:1, or 1 male for every female birth. Yet, in some countries, the sex ratio is not even close to equal and presents drastically low numbers for females. Can you name them?
The reason for the Vatican's figures is obvious. Presumably in those other countries differing >5 percentage points from the mean, the cause is migrant workers being predominantly male? I hope.
Yes the Vatican is pretty obvious! For the others my research has uncovered that an imbalance between the sexes is caused by many things including war, gender-selective abortions, and mass migration.