Preliminary inquiry into the difference in sex ratio at birth in China]

Based on population statistics from China's 2nd and 3rd national censuses, China's unusually high male/female birth rates are examined. It appears that the lower male/female birth rates are generally found in China's minority-populated autonomous regions. Xizang Autonomous Region (Tibet) has the nation's lowest male/female birth ratio of 101.3; the highest ratio, 112.5, is in Anhui province; the national average for 1981 was 108.47. Although geographic, socioeconomic, and other factors may be attributed to regional differences, it is maintained that the high male/female birth rate is universal throughout China. The significant difference between the relatively high male/female birth rate in China's urban areas in 1981 (109.9), and the lower rate in the rural areas (107.6) is challenged by the author, who suggests that China's urban statistics are unquestionably more reliable than the rural statistics. The author suggests that factors such as the importance of raising male offspring, China's traditionally male-dominated family system, and the desire for male farm workers is strongest in China's rural sector. The current male/female birth rate is not a recent trend; prior to 1949, the male/female birth rate ranged from 110 to 115.     

Education and gender bias in the sex ratio at birth: Evidence from India

This article investigates the possible existence of a nonlinear link between female disadvantage in natality and education. To this end, we devise a theoretical model based on the key role of social interaction in explaining people’s acquisition of preferences, which justifies the existence of a nonmonotonic relationship between female disadvantage in natality and education. The empirical validity of the proposed model is examined for the case of India, using district-level data. In this context, our econometric analysis pays particular attention to the role of spatial dependence to avoid any potential problems of misspecification. The results confirm that the relationship between the sex ratio at birth and education in India follows an inverted U-shape. This finding is robust to the inclusion of additional explanatory variables in the analysis, and to the choice of the spatial weight matrix used to quantify the spatial interdependence between the sample districts.     

Indirect evidence of the contribution of prenatal sex selection practices to the high sex ratio at birth in Vietnam

This paper reports indirect evidence that prenatal sex selection is a contributor to the recent increase in sex ratio at birth in Vietnam. The paper uses birth data from the Population Change Survey 2006 to assess the associations between sex ratio at birth and variables that predict increased opportunities to practise prenatal sex selection, including maternal knowledge of foetal sex before birth, the use of ultrasound for foetal sex determination, the gestation week when foetal sex was disclosed, and access to abortion services. The high sex ratio of most recent births was significantly associated with the use of ultrasound to determine the foetal sex in gestation weeks 12–22 and with access to family planning services that provide abortion. Prenatal sex selection in health facilities are likely to contribute to the recent increase in sex ratio at birth in Vietnam.     

The imbalance of sex ratio at birth,and its causes and countermeasures in China

This news brief focuses on the sex ratio at birth (SRB) in China, its causes, and remedial efforts. A SRB has been evident since the 1980s. The SRB increased from 108.48 male/100 female births to 116.30 male/100 female births during 1981-94. A normal SRB in China during 1940-94 would have been 107 male/100 female births. The SRB rose every year after 1985, with the exception of 1988. Male births increased, while female births decreased. SRB declined with age. The sex ratio in 1991, was 112.3 for children aged 0-4 years, 108.38 for children aged 5-9 years, and 106.56 for children aged 10-14 years. SRB values were higher in more populous provinces and lower in less populous provinces. SRB values were lower in northwestern China than in southeastern China. SRB values of minorities were lower than the Han ethnic group. A high SRB will increase the proportion single in later years. In 1990, 7.86 million people aged 30-40 years were single, of whom 94.32% were males. The SRB is caused by second, third, or higher birth orders. In 1993, sex ratios were 105.60 for first births, 130.22 for second births, and 126.12 for third births. The imbalance is attributed to a preference for sons as inheritors of blood ties and as family physical laborers. The imbalance is due to strict birth control and people's refusal to report female births. There is a need to increase awareness of the consequences, to increase old-age pensions and social security, to increase women's status, and to prohibit sex determination of a fetus. The family structure should emphasize its consumptive capacity rather than its function as a production unit.     

The comparative analysis of the dynamics of childbearing women's birth at Yanging County, Beijing]

At the end of 1981 Yanging County had 26 communes, 375 production brigades and a total population of 211,098. A random sampling of 5.07% of the production brigades was taken, which included teams from the plains as well as mountainous regions. The sample had a population of 10,888, or 5.16% of the entire county, among whom 189 subjects were interviewed. These 189 women, whose ages ranged from 35-67, were divided into 5 birth year cohorts (1914, 1920, 1930, 1940, 1946). Findings include: 1) Age at marriage: the average age at marriage (about 17 years) between the 1914 and 1946 groups rose 1.82 years, indicating that early marriage was the norm. The time between marriage and 1st birth has shortened. 2) Fertility data: from 1914 to 1946 the lifetime fertility rate tended to decline from 4.60 to 3.70, but the 1930 cohort was the highest (6.42), followed by the 1920 cohort (6.26). The fertility rate of the 1914 cohort tended to rise in the 1950s after already having reached a peak in the early 1940s, probably because after Liberation fertility rose due to a higher standard of living and a stablized society. The fertility of the 1930 cohort was highest around 1963 when they were already 30 years old. The fertility of the 1940 cohort was also highest beginning around 1963. In both cases, the reason probably was because the national economy improved at this time. Indeed, the national fertility rate rose from a 1960 low of 20.9/1000 to 43.6/1000 in 1963. 3) Contraceptive use: prior to 1972 before there was an offical birth control policy, a sizeable number of women already desired to use contraceptives, the reason being most of these women felt they already had enough children. However, many women did use contraceptives in response to the call to do so. 4) Factors influencing fertility standards: in general, the less a woman's education and the lower her income, the higher was her standard of fertility, and vice versa. 5) The percentage of women who had children who died before the age of 15 ranged from 35.9% of the 67 year olds to 12.6% of the 35 year olds.     

Sex ratio at birth for urban and rural areas

Previous studies show that sex ratio at birth in China's urban areas is usually higher than that of rural areas. The higher proportion of 1st births in urban areas was once taken to explain the cause for the higher sex ratio. The data of the 1982 fertility sampling survey show that the sex ratio at birth during the period from 1964 to 1981 remains higher in the urban areas (108.0) than in the rural areas (107.8). Further studies are yet needed on the differentials in sex ratios at birth between urban and rural areas and on their causes. The sex ratio in 1981 of the 29 provinces, municipalities and autonomous regions in China's mainland was 108.5, somewhat higher than that of most countries in the world. 2 things account for the occurrence. 1 is that, biologically, certain particularities may exist in the sex ratio at birth of China's population, for the ratio varies with ethnic groups, nationalities and regions. The other is that, sociologically, female infants may be underreported in some areas and the phenomenon of infanticide left over by history still exists in some isolated cases. These surveys suggest that a certain specific characteristic does exist in the sex ratio at birth of China's urban areas, but they also contribute to the explanation of the higher sex ratio at birth of the total population of the country.     

A study on mortality rates and expectation of life at birth in demography]

An "age-time-area diagram" (referred to as a-t diagram) which is used as the basis for discussing different used and applications of variously defined mortality rates, as well two kinds of measurements for life expectancy is proprosed. The proposal is built upon the Lexis diagram. The a-t diagram is used to define a new way of measuring child mortality, projecting population, and proposing a formula for measuring successive and nonsuccessive life expectancy.     

The pattern of changing trends and the regional differences in the sex ratio at birth: evidence from Korea and Jilin Province,China

"The main purpose of this study is to develop explanations for the pattern of recently changing trends and regional differences in the sex ratio at birth in Korea and for Koreans in Jilin Province and Yanbian Autonomous Prefecture, China.... The findings suggest that, since the mid-1980s, sex ratios at birth have risen remarkably in Korea.... This paper also highlights the recent increase in the sex ratio at birth for the Korean population in China, residing in urban areas densely populated with Koreans. As the key forces behind the regional differences in sex ratios at birth, the effects of son-selective reproductive behaviors, which in turn, are affected by the community characteristics, are stressed."     

Understanding the sex ratio in India: A simulation approach

The highly masculine sex ratio in India has increased substantially in the twentieth century, in contrast to most other countries in the world. Competing arguments alternatively posit under-enumeration, highly masculine sex ratios at birth, or excess female mortality throughout the life course as the factors underlying the level of the overall sex ratio; these arguments have not been resolved. Based on population projections that simulate population dynamics, our findings show that small differences in mortality at young ages, persisting over a long period, as well as a sex ratio at birth of 106 males per 100 females, result in a highly masculine population sex ratio.     

[An analysis of the sex ratios at birth of China].]

The sex ratio at birth in China is analyzed using data from the 1982 census. The focus is on geographic differentials in sex distribution and the impact of population density on those differentials. Findings indicate that the sex ratio at birth was lower in urban populations than in rural populations.     

A general review of the discussion at the Beijing International Symposium on Population and Development]

A general review of papers and discussions at the Beijing International Symposium on Population and Development held December 10-14, 1984 is presented. Discussions on population and development included China's population change 1949-1982, impacts of economic change on Tianjin's population, the population factor in economic development policy-making, Japanese population and development, recent population development in Hungary, population and economy, comprehensive long-term population development in Russia, fertility rate change factors in China, Shanghai's population change, and population and economic development in Mian County, Shaanxi Province. Fertility rate changes were discussed, including multinational borderline value assumptions, recent trends in life span fertility rate in China, fertility rate in Jiangsu Province, fertility rate change in Zhejiang Province, and sterilization in Yangjiaping, Thailand. Population and employment discussions included the economic impact of world population change, the 1984 International Population Conference, changes in economically productive population and employment strategy, employed/unemployed populations in Guangdong Province, and the economic composition of China's population. Urbanization discussions covered population and development methodological problems, population growth and economic development in the Pacific region, surplus rural population transfer and economic development in China, urbanization analysis, trends and urban population distribution problems, and Laioning Province population development. Issues in migration, population distribution, and regional population included migration and development of the Great Northwest, internal migration to Beijing, Chinese population growth and economic development by major region, and current population changes of Chinese Tibetans. Under social problems of population, discussions included women's status, development and population change, Shanghai's aging trend, analysis of the aged population, analysis of educational quality in Anhui Province, and the retirement system in Chinese villages.     

Survey on sex ratio of the children from one-child families in Shihezi in the Xinjiang Uigur autonomous region]

A survey of 1 child families in the Shihezi area showed a higher ratio of boys, 920 boys vs. 822 girls (1.12:1.00). There was also a higher ratio of boys among children born between 1975-1980, but the proportion of girls was higher among children born before 1974. The ratio of boys was higher among firstborn children born between 1976-1980 (1.086:1.00), while the sex ratio was 1.00 among 2nd born children born between 1976-1980. School children between age 6-18 showed 6266 boys and 6218 girls (1.01:1.00). The sex ratio of the total population in the Shihezi area was 1.05:1:00; this coincides with our national ratio of 1.08:1.00 (1953 census) and the world sex ratio of 1.0035:1.00 in 1975. The universal occurrence of more males than females is probably a result of physiological factors. It is actually beneficial to the country to have a slightly higher ratio of males because many jobs are more suitable for men because of their physical condition and the accidental death rate is also higher for men. The slightly higher percentage of boys among single child families was not statistically significant (P0.05).     

Sex ratio at birth: Values,variance, and some determinants

This paper examines the values, variance and some possible determinants of sex ratios for the first child and for all children in expected and desired families. For adults in Tallahassee, Florida, it was found that a large majority of respondents within sixty demographic categories chose males for their first child. Of those who actually had girls for their first child, a plurality would, nevertheless, prefer a first boy in their desired family. It was hypothesized and demonstrated that sex-role ideologies were a strong predictor of variance in first-child sex preferences. Sex ratios for all children in expected and desired families were 116 and 113, respectively. If people could choose the sex of their future children, these data suggest that several population parameters might be significantly altered; a preliminary model is outlined which might project some of these changes.     

Preliminary evidence regarding the hypothesis that the sex ratio at sexual maturity may affect longevity in men

In human populations, variation in mate availability has been linked to various biological and social outcomes, but the possible effect of mate availability on health or survival has not been studied. Unbalanced sex ratios are a concern in many parts of the world, and their implications for the health and survival of the constituent individuals warrant careful investigation. We indexed mate availability with contextual sex ratios and investigated the hypothesis that the sex ratio at sexual maturity might be associated with long-term survival for men. Using two unique data sets of 7,683,462 and 4,183 men who were followed for more than 50 years, we found that men who reached their sexual maturity in an environment with higher sex ratios (i. e., higher proportions ofreproductively ready men) appeared to suffer higher long-term mortality risks than those in an environment with lower sex ratios. Mate availability at sexual maturity may be linked via several biological and social mechanisms to long-term survival in men.     

Host-size-dependent sex ratio in a parasitoid wasp

Charnov's host-size model explains parasitoid host-size-dependent sex ratio as an adaptive consequence when there is a differential effect of host size on the offspring fitness of parasitoid males versus females. This article tests the predictions and the assumptions of the host-size model. The parasitoid wasp Pimpla nipponica Uchida (Hymenoptera: Ichneumonidae) laid more female eggs in larger or fresher host pupae when choice among hosts of different sizes or ages was allowed. Then, whether an asymmetrical effect of host size and age on the fitness of females versus males existed in P. nipponica was examined. Larger or fresher host pupae yielded larger wasps. Larger females lived longer, whereas male size did not influence male longevity. Large males mated successfully with relatively large females but failed with small females, whereas small males could mate successfully either with small or with large females. Thus, small-male advantages were found, and this held true even under male–male competition. Ovariole and egg numbers at any one time did not differ among females of different sizes. Larger females attained higher oviposition success and spent less time and energy for oviposition in hosts. Larger females produced more eggs from a single host meal. Taken together, females gained more, and males lost more, by being large. Host size and age thus asymmetrically affected the fitness of offspring males versus females through the relationships between host size or hast age and wasp size, which means the basic assumption of the host-size model was satisfied. Therefore, sex ratio control by P. nipponica in response to host size and age is adaptive. Received: November 13, 1998 / Accepted: January 18, 1999     

A preliminary analysis of the high birth rate in India]

The author first provides some basic demographic data for India and points out that the current annual rate of population growth of 2.45 percent is slightly higher than the annual increase in food production. Problems in the areas of employment, education, housing, and transportation, as well as the general problem of poverty, are seen as a consequence of this imbalance. The lack of success of the national family planning program is attributed primarily to the failure to achieve a satisfactory rate of economic growth. Contributory factors include early marriage, the low status of women, the desire for large families, and administrative problems associated with the family planning program.     

Some problems found in a retrospective survey of fertility in Haidian district, Beijing]

The results of a fertility survey undertaken in the Haidian district of Beijing, China, in 1981 are presented. The data are from a random sample of 6.3 percent of the population at selected ages. The results show an increase in age at marriage, a decrease in the interval between marriage and first birth, and a decrease in the number of pregnancies associated with the family planning program.     

The effect of natural disaster on fertility,birth spacing,and child sex ratio: evidence from a major earthquake in India

Natural disasters can lead to significant changes in health, economic, and demographic outcomes. However, the demographic effects of earthquakes have been studied only to a limited degree. This paper examines the effect of the 2001 Gujarat earthquake on reproductive outcomes. This earthquake killed more than 20,000 people; injured 167,000; and caused massive losses to property and civic assets. Using data from two large-scale District-Level Household Surveys (2002–2004 and 2007–2008), we employ difference-in-difference and fixed-effect regression models to compare the outcomes across earthquake-affected districts and their neighboring districts during 5 years before and after the earthquake. We find that the earthquake led to significant rises in childbirth rates. It also reduced birth spacing among uneducated, tribal, and Muslim women, and the incidence of male births among rural women. We find considerable variation in the demographic effects of the earthquake across location, household socioeconomic status, and parental age and education.