Related Experiment Video

Updated: Jun 4, 2026

Physical Activity Measurement in Children Accepting Table Tennis Training
06:51

Physical Activity Measurement in Children Accepting Table Tennis Training

Published on: July 27, 2022

Child underreporting, fertility, and sex ratio imbalance in China

Daniel Goodkind1

  • 1U.S. Census Bureau, Washington, DC, USA. daniel.m.goodkind@census.gov

Demography
|February 22, 2011
PubMed

Insights

Child underreporting in China significantly increased after 1991, impacting fertility and sex ratio estimates. New analysis reveals higher unreported children and lower fertility rates than previously assumed.

Area of Science:

  • Demography
  • Population Studies
  • Sociology

Background:

  • Child underreporting is a significant issue in Chinese demographic studies.
  • The birth planning system's stricter enforcement in 1991 likely influenced underreporting.
  • Existing fertility and sex ratio estimates may be inaccurate due to this underreporting.

Purpose of the Study:

  • To quantify child underreporting in China using intercensal comparisons.
  • To reassess fertility estimates based on corrected underreporting data.
  • To analyze the impact of underreporting on sex ratio at birth calculations.

Main Methods:

  • Intercensal comparisons of census data to identify underreporting trends.
  • Triangulation of evidence to estimate the percentage of unreported children.
  • Analysis of sex ratios of births and children, accounting for underreporting.

Main Results:

  • An estimated 19% of children aged 0-4 were unreported in the 2000 Chinese census, a substantial increase from 1990.
  • China's fertility rate in the late 1990s was likely lower than officially reported.
  • Estimated sex ratios at birth are lower than reported ratios due to excess underreporting of daughters.

Conclusions:

  • Child underreporting, particularly of daughters, significantly distorts demographic measures in China.
  • Fertility estimates require revision due to increased underreporting post-1991.
  • Sex ratio imbalances are complex, influenced by underreporting and potentially by specific population policies.

Related Concept Videos

The Ratio of X Chromosome to Autosomes02:45

The Ratio of X Chromosome to Autosomes

In most organisms, sex is determined by the ratio of X and Y chromosomes. However, in some organisms, such as Drosophila and C.elegans, sex is determined by the ratio of the number of X chromosomes to the number of sets of autosomes. The Y chromosome in Drosophila is active but does not determine sex. It contains genes responsible for the production of sperms in adult flies.  
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female Drosophila...
Socioemotional Experience and Gender Development01:30

Socioemotional Experience and Gender Development

Social-emotional experiences and cultural influences play significant roles in shaping gender development. During middle childhood, from ages 6 to 11, peer groups become dominant in reinforcing gender norms. Children in this age group often align with same-gender peer groups, which actively encourage behaviors that conform to traditional gender roles. For instance, boys may be discouraged from engaging in activities perceived as feminine, reinforcing culturally dictated norms about masculinity...
Infertility in Males01:23

Infertility in Males

Male infertility affects millions of couples worldwide, arising from various factors that impact different stages of the reproductive process. An endocrine imbalance resulting from conditions like hypogonadism, Klinefelter syndrome, or pituitary disorders can disrupt hormone levels and reduce sperm production. Testicular defects, such as tumors, cryptorchidism, atrophic testes, abnormal sperm morphology, and low sperm count or motility, may arise due to genetic factors, structural...
Regression Toward the Mean01:52

Regression Toward the Mean

Regression toward the mean (“RTM”) is a phenomenon in which extremely high or low values—for example, and individual’s blood pressure at a particular moment—appear closer to a group’s average upon remeasuring. Although this statistical peculiarity is the result of random error and chance, it has been problematic across various medical, scientific, financial and psychological applications. In particular, RTM, if not taken into account, can interfere when researchers try to extrapolate results...
Nondisjunction01:29

Nondisjunction

During meiosis, chromosomes occasionally separate improperly. This occurs due to failure of homologous chromosome separation during meiosis I or failed sister chromatid separation during meiosis II. In some species, notably plants, nondisjunction can result in an organism with an entire additional set of chromosomes, which is called polyploidy. In humans, nondisjunction can occur during male or female gametogenesis and the resulting gametes possess one too many or one too few chromosomes.
Nondisjunction01:21

Nondisjunction

Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate correctly and move to the opposite poles of the cells. This produces daughter cells with abnormal chromosome numbers.  Nondisjunction is common during anaphase I or anaphase II of meiosis.  Mutations in synaptonemal complex proteins that attach homologous chromosomes increase the chances of nondisjunction in anaphase I of meiosis I. In contrast, mutations in topoisomerases and condensins that hold sister...