Sex Ratio at Birth (SRB)

Sex Ratio at Birth (SRB) is a demographic indicator expressing the number of male live births relative to female live births, conventionally stated as males per 100 females or, in United Nations practice, males per 1,000 females. It is distinct from the overall sex ratio, which counts the entire population. The biological norm, established through extensive demographic study, falls within a narrow band of 103 to 107 males per 100 females, a slight male surplus that compensates for higher male mortality in infancy and childhood. Amartya Sen's 1990 essay "More Than 100 Million Women Are Missing" gave the metric global political salience by quantifying the demographic deficit produced by son preference. In India the indicator is tracked through the Sample Registration System (SRS) of the Office of the Registrar General and Census Commissioner, the decennial Census, and household surveys including the National Family Health Survey (NFHS).

The mechanics of SRB measurement begin with the registration or survey enumeration of live births classified by sex over a reference period, usually a calendar year or a three-year moving average to smooth small-sample volatility. Analysts divide the count of male live births by the count of female live births and multiply by 100. Because the natural ratio is biologically stable, any sustained deviation above roughly 107 is read as evidence of prenatal sex selection through sex-determination diagnostics followed by selective abortion of female foetuses, or in rarer documented cases female infanticide and the differential under-registration of girl births. The SRS publishes three-year averages precisely to distinguish a genuine signal from statistical noise in states or districts with small annual birth cohorts.

A related construct, the Child Sex Ratio (CSR), counts girls per 1,000 boys in the 0–6 age group and is reported through the Census; it captures both birth-stage selection and post-birth differential mortality and neglect during early childhood. SRB and CSR move together but are not identical, because the CSR accumulates the effects of excess female child mortality after birth. India's Census 2011 recorded a CSR of 919 girls per 1,000 boys, the lowest since independence and a decline from 927 in 2001, which propelled the policy response. The NFHS-5 (2019–21) reported an SRB of 929 females per 1,000 males at the all-India level, an improvement over NFHS-4's 919, though several northern and western states remained skewed.

The policy architecture addressing adverse SRB in India rests on the Pre-Conception and Pre-Natal Diagnostic Techniques (Prohibition of Sex Selection) Act, 1994 (the PCPNDT Act, amended in 2003), which prohibits the communication of foetal sex and regulates ultrasonography clinics. The Beti Bachao Beti Padhao scheme, launched at Panipat, Haryana, on 22 January 2015 by Prime Minister Narendra Modi, combined enforcement, awareness, and conditional incentives, initially targeting 100 gender-critical districts. Haryana, historically among the most skewed states, reported district-level SRB improvements through this period. Internationally, the People's Republic of China, where the one-child policy intensified son preference, recorded SRBs exceeding 118 in the early 2000s, while Vietnam, Azerbaijan, Armenia, and Georgia also display documented imbalances tracked by the United Nations Population Fund (UNFPA).

SRB must be carefully distinguished from the overall (or population) sex ratio, which India expresses as females per 1,000 males across the whole population and which is shaped additionally by adult migration, life expectancy differentials, and historical mortality—India's 2011 figure was 943. It is also distinct from the maternal mortality ratio and from fertility measures such as the total fertility rate, though son preference interacts with declining fertility: as families desire fewer children, the pressure to ensure that at least one is male can intensify selection, a phenomenon demographers term the "fertility squeeze." Confusing SRB with the aggregate sex ratio is a common analytical error, since the two can diverge sharply in populations with high female out-migration or sex-differentiated mortality.

Controversies surround both measurement and interpretation. Under-registration of female births inflates apparent SRB in weak civil-registration regimes, so improvements in the indicator may partly reflect better registration rather than reduced selection. Enforcement of the PCPNDT Act has been uneven, with low conviction rates and the migration of sex-determination services across state and international borders. Critics also caution that conditional cash transfers can instrumentalise daughters without altering underlying patriarchal valuation. Recent developments include UNFPA's emphasis on the long-run "marriage squeeze"—a future deficit of brides in China and India producing surplus unmarried men—and debates over whether some celebrated state-level reversals reflect genuine behavioural change or data artefacts. The COVID-19 pandemic disrupted both health services and registration, complicating trend analysis for 2020–22.

For the working practitioner—whether a UPSC aspirant preparing General Studies Paper I, a desk officer drafting a population brief, or a development analyst—SRB is a compact, internationally comparable diagnostic of gender discrimination operating before and at birth. Its value lies in precision: knowing the biological baseline of 103–107 allows immediate identification of anomalous populations, while pairing SRB with CSR isolates prenatal selection from post-natal neglect. Practitioners should cite the source instrument (SRS, Census, or NFHS), specify whether figures are expressed per 100 or per 1,000, and treat single-year district figures with caution. Used rigorously, the indicator informs the design of enforcement, incentive, and awareness interventions and anchors India's commitments under Sustainable Development Goal 5 on gender equality.