The reported sex ratio at birth is the
number of male births per 100 female births
enumerated in a census, a survey, or civil
registration. Theoretically, the reported sex
ratio should be equal to the “true” sex ratio
(i.e., the number of males per 100 females
born in a population), which is biologically
stable around the value of 106 in the absence
of social and behavioral interference.
Yet, by using survey and census data,
many studies have identified discrepancies
between true and reported sex ratios at birth
in most countries, especially in the developing
world. Three main proximate causes of
this “imbalance” of reported sex ratios at
birth have generally been identified: female
infanticide, underreporting of girls, and sexselective
abortion practices.1 Important
distant causes of abnormally high sex ratios
at birth are usually acknowledged to be the
implementation of family planning policies
targeted at fertility reduction and strong
preference for sons over daughters. In fact,
in countries where son preferences do exist,
fertility decline has generally resulted in
more skewed sex ratios at birth – a phenomenon
that has been observed in Taiwan,
Korea,2 India,3 Bangladesh, and China.4
Almost all studies on the imbalance of
reported sex ratios at birth rely on two main
implicit assumptions: 1) distant causes
provide the context in which the imbalance
of reported sex ratios at birth arises as a
result of its proximate causes; and 2) the
measurement process of the sex ratio at birth
– from the actual data collection to the
release of the final results – is not
systematically affected by the implementation
of specific family planning
policies and/or by the existence of gender
preferences for children. In other words, it is
generally assumed that the social, cultural,
and political context might create incentives
for sex-selective abortion, sex-selective
underreporting, and sex-selective infanticide,
but would not affect the way through which
births are actually measured. The context isnot supposed to exert any systematic effect
on the measurement process of the sex ratio
at birth, and its eventual imbalance is
supposed to be an “objective” circumstance.
The assumption about the validity of the
indicators utilized and the reliability of the
methods of data collection – in the analysis
of the imbalance of reported sex ratios as
well as of most other topics – is indeed a
common one in demographic literature. The
geographic, political, social, and economic
context is generally supposed to affect the
quality of demographic data in a random,
non-systematic way. Yet, what if a specific
context does create incentives, at the individual
and administrative level, to purposely
misreport and mismeasure the actual number
of births, abortions, or infant
deaths?