The effect of illegitimacy on U.S. general fertility rates and population growth

Abstract Illegitimacy and bridal pregnancy has attracted the attention of scholars concerned with a variety of plausible causes and consequences ofbirths conceived out of wedlock. Sociologists have expressed concern with the impact of such births on maternal and child health, family stability and the economic status offamilies. Although demographers have described trends in various populations, and have occasionally suggested that births conceived out of wedlock influence general fertility rates and cohort fertility, measures of the demographic impact of illegitimate or premaritally conceived births have not been assessed. While it seems obvious that a change in births conceived out of wedlock will affect change in a general fertility rate, this finding would not automatically allow the conclusion that cohort fertility would change because a change in the rate of births conceived out of wedlock occurred.     

Sweden faces zero population growth

In this discussion of Sweden as it approaches zero population growth, focus is on the following: population growth in perspective, fertility trends (childbearing concentrated and cohort versus period fertility), marital status (non-marital cohabitation, out-of-wedlock births, and divorce), women's changing status (increasing education and increasing employment), constraints and supports for women's dual role (family allowances and housing), birth control (contraceptive methods and practice and abortion), mortality trends, changing age structure and the elderly (average population age and proportion of elderly and cost of elderly support), international migration (from emigration to immigration and demographic impact of immigration), immigration policy, recent population debate (immigration issues and facing zero population growth). Since 1900 the primary features of Sweden's demographic history are a continuing decline in the birth rate to very low levels -- relieved by some upward movement in the 1940s and 1960s -- and a marked shift in the migration balance from emigration to immigration. It is almost entirely because of immigration that Sweden's population growth rate has not yet turned negative. If Swedish women were to continue to bear children at the rate that all women in the reproductive ages actually did in 1978, each women would end up with an average well below the level necessary to exactly replace each adult in the population leaving migration out, an annual total fertility rate of 2.1 children per woman would have to be sustained for births and deaths to be in balance under the low mortality conditions prevaling in Sweden.     

Three methods of estimating births averted nationally by contraception

This paper compares the performance of three methods applicable to national-level demographic data of estimating births averted as a consequence of contraceptive practice. Two are based on the relationship between the general fertility rate (GFR) or total fertility (TFR) and contraceptive prevalence, while the third uses Bongaarts' proximate determinants (PD) model. Estimates of the number of births averted and the percentage by which the number would have increased in the absence of contraception are consistent between the GFR-based and TFR-based methods, but in general lower than the estimates generated by the PD-based method, except for a few high-contraceptive-prevalence countries. For 156 countries and areas around the world the estimated number of births that would have occurred in a recent year in the absence of contraception--the average of the estimates of the three methods--is approximately 230 million, which is more than the estimated 129 million births that actually occurred.     

The time response in averted births

Abstract A calculation of the timing of births that are averted may seem a curious exercise, when not only do the births in question not occur, but the corresponding conceptions may never have existed. However, such a calculation may have considerable use. In order to assess the likely direct impact of a contraceptive programme on birth rates it is useful to estimate the number of births that would, in the absence of the programme, have occurred among the couples who accept it. Moreover, some time would necessarily elapse before a new 'steady state' in fertility could be reached, even if the programme and the potentially fertile population did not change in any way; and it is worth while to seek to find the times (for a few years after the start of a programme) when the (averted) births would have occurred in its absence, and to examine any inherent oscillations produced in birth rates by it. This question is considered below only for groups of women aged 20 at marriage (a state which is taken to be the start of regular exposure to the risk of conception), but the same methods are applicable to other ages, (possibly allowing for mortality) and appropriate combinations of age groups and cohorts in the fertile range may be used to estimate changes in fertility and reproduction rates expected from a programme, subject to given conditions, for several years after its start. The methods can also be generalised, by means of convolution, to contraceptive programmes that change with time, but these are not considered further.     

The Apparent Failure of Russia's Pronatalist Family Policies

Russia has a history of pronatalist policies dating back to the 1930s. Two sets of pronatalist measures were implemented during the past 40 years. The one designed in the early 1980s proved to be a clear failure. Instead of raising fertility, completed cohort fertility declined from 1.8 births per woman for the 1960 birth cohort to 1.6 for the 1968 cohort. The government of President Putin became concerned with the dire demographic conditions of high mortality and low fertility in Russia in the 1990s and early 2000s. A comprehensive set of pronatalist measures came into effect in January 2007. The period total fertility rate increased from 1.3 births per woman in 2006 to 1.6 in 2011, which the authorities view as an unqualified success. An unbiased demographic evaluation as well as analyses of Russian experts reveals that apparently the measures mainly caused a lowering of the age at birth and shortening of birth intervals. It appears that any real fertility increase is questionable, i.e. cohort fertility is not likely to increase appreciably. The recent pronatalist measures are likely to turn out to be a failure.     

Fertility of Australian birth cohorts: Components and differentials

The paper examines the change in the level and pattern of fertility that took place in the post-1971 period, and the downward completed fertility of successive generations of Australian women born since 1933–37. The change in cohort fertility is assessed in terms of the cohort parity progression ratios, and the four components of cohort total fertility: the proportion of women who proceeded to have a birth, mean age at first birth, mean age at last birth, and average interbirth interval for women who had at least two births. The other aspects discussed are the cohort fertility differentials and the implications of the current trends for future fertility in Australia.     

应用队列累计生育率分析我国生育水平变动趋势——兼与郭志刚教授讨论

本文对反映生育水平的两个基本指标——总和生育率和队列累计生育率进行分析,肯定多年来多个调查所得到的队列累计生育率的数据质量。尽管队列累计生育率反映的是"过去"而不是"当前"的实际生育水平,但历次调查所反映出的1990年代以来生育水平变化趋势是持续下降,并推断近几年的总和生育率已经下降到1.6以下。     

Cohort estimates of nonmarital fertility for U.S. Women

Historical trends in U.S. nonmarital fertility have been compiled almost exclusively from vital statistics on births. This paper complements this historical record by providing cohort estimates of nonmarital fertility for cohorts of U.S. women spanning approximately 50 years of cohort experience. Life table estimates using retrospective marital and fertility histories in the June 1980, 1985, 1990, and 1995 Current Population Surveys reveal nonnegligible levels of nonmarital fertility historically. For women born between 1925 and 1929, nearly 1 in 10 had at least one nonmarital birth by age 30. For women born between 1965 and 1969, more than 1 of 4 had one or more nonmarital births by age 30, with roughly 1 of5 white, 3 of 5 black, and 1 in 3 Hispanic women having at least one nonmarital birth by age 30. Life table estimates reveal a twofold increase between ages 20 and 30 in the percentage of women with at least one child outside of formal marriage for all cohorts of white and Hispanic women, and an increase of roughly two-thirds for all cohorts of black women. I also document qualitative differences in nonmarital fertility by race/ethnicity, with the percentage of nonmarital births following a divorce or marital separation for white women approximately twice that for black or Hispanic women. Finally, I introduce a new measure, the cohort nonmarital fertility ratio (CNMFR), which provides a cohort complement to the standard period nonmarital fertility ratio. Conservative estimates reveal a roughly threefold increase in the CNMFR for women born from 1925-1929 to 1950-1954 for both whites and blacks, despite substantially higher levels of nonmarital fertility among black women. Overall, these findings reveal surprisingly high levels of nonmarital fertility for women born since the 1920s and confirm that nonmarital fertility has become an increasingly substantial component of overall U.S. fertility.     

East Asian childbearing patterns and policy developments

Childbearing behavior in East Asian countries has changed rapidly during the past half century from an average of five to seven children per family, to replacement-level fertility, and subsequently to unprecedentedly low levels, the lowest in the world. This article analyzes fertility trends in Hong Kong, Japan, singapore, south Korea, and Taiwan using cohort fertility data and methods, then examines social and economic causes of the childbearing trends, and surveys policies pursued to reverse the fertility trends. Postponement of childbearing started in the 1970s with continuously fewer delayed births being "recuperated," which resulted in ultra-low fertility. A rapid expansion of education and employment among women in a patriarchal environment has generated a stark dilemma for women who would like to combine childbearing with a career. Policy responses have been slow, with a more serious attempt to address issues in recent years. Thus far public and private institutions are not devoting sufficient attention to generating broad social change supportive of parenting.     

Regression analysis of the relationship between the birth rate and proportion of first order births in 1981]

Generally speaking, various fertility indicators such as the birth rate, average fertility rate, and total fertility rate have a close relationship. Various regression analyses have also been made by using different data on population statistics to describe their internal relationships. A regression analysis of the relationship between the birth rate and proportion of first order births, however, has not been made. Data collected by family planning staff at various places show that the places with a high rate of first order births normally have a lower birth rate, and the places with a low rate of first order births very often have a high birth rate. From here we may find that the proportion of the first order births is moving in two opposite directions, and there is no determined relationship between them. It is impossible to use one indicator to calculate the other's indicator. Only a regression analysis can be made to study the relationship between the two. The birth rate and proportion of first order births in 1981 showed some negative relationship, but the use of a regression equation should still be restricted. The regression equation between the birth rate and proportion of first order births may reflect a correct relationship when the region and the number of first order births are fixed. Therefore, any factor which has an impact on the number of first order births also has an influence on the use of regression equation.     

Limit cycle oscillations of the human population

This paper investigates a mathematical model for the growth of an age-structured population. The model includes the idea (due to Easterlin) that fertility is affected by the size of the cohort in which an individual is born. It is important to note that the model investigated represents only a reasonable first step in the direction of reality from the unrealistic assumption that mortality and fertility do not change with passing time. It is shown that this general model can lead to self-excited, persistent oscillations (called limit cycles in mathematical parlance) of the birth trajectory of the population. Using data for the United States from the twentieth century, it is shown that variations in the number of births are consistent with the model discussed.     

The Quality of Male Fertility Data in Major U.S. Surveys

Researchers continue to question fathers’ willingness to report their biological children in surveys and the ability of surveys to adequately represent fathers. To address these concerns, this study evaluates the quality of men’s fertility data in the 1979 and 1997 cohorts of the National Longitudinal Survey of Youth (NLSY79 and NLSY97) and in the 2002 National Survey of Family Growth (NSFG). Comparing fertility rates in each survey with population rates based on data from Vital Statistics and the U.S. Census Bureau, we document how the incomplete reporting of births in different surveys varies according to men’s characteristics, including their age, race, marital status, and birth cohort. In addition, we use Monte Carlo simulations based on the NSFG data to demonstrate how birth underreporting biases associations between early parenthood and its antecedents. We find that in the NSFG, roughly four out of five early births were reported; but in the NLSY79 and NLSY97, almost nine-tenths of early births were reported. In all three surveys, incomplete reporting was especially pronounced for nonmarital births. Our results suggest that the quality of male fertility data is strongly linked to survey design and that it has implications for models of early male fertility.     

The Surprising Global Variation in Replacement Fertility

It is frequently assumed by the general public and alsoby some population experts that the value ofreplacement-level fertility is everywhere an averageof 2.1 lifetime births per woman. Nothing could befurther from the truth. The global variation inreplacement fertility is substantial, ranging by almost1.4 live births from less than 2.1 to nearly 3.5. Thisrange is due almost entirely to cross-country differencesin mortality, concentrated in the less developed world.Policy makers need to be sensitive to own-countryreplacement rates. Failure to do so could result infertility levels that are below replacement and lead tolong-run population decline. For example, the currentreplacement total fertility rate for the East Africa regionis 2.94. Lowering fertility to 2.10 would, under currentmortality conditions, result in a regional birthrate 29 percentbelow replacement.     

Can We Still Learn Something From the Relationship Between Fertility and Mother’s Employment? Evidence From Developing Countries

In this work, I study the impact of fertility on mothers’ employment for a sample of developing countries. Using the event of multiple births as an instrumental variable (IV) for fertility, I find that having children has a negative impact on female employment. In addition, three types of heterogeneity are found. First, the magnitude of the impact depends on the birth at which the increase in fertility takes place. Second, the types of jobs affected by a fertility shock (multiple births) are jobs identified with a higher degree of informality, such as self-employment or unpaid jobs. Finally, the heterogeneity analysis reveals that an unexpected change in fertility is stronger at a higher education level of the mother and in urban areas.     

Migration, fertility, and state policy in Hubei Province, China

Despite China s one-child family planning policy, the nation experienced a slight rise in the birth rate in the mid-1980s. Many observers attributed this rise to the heightened fertility of those rural-to-urban migrants who moved without a change in registration (temporary migrants), presumably to avoid the surveillance of family planning programs at origin and destination. Using a sequential logit analysis with life-history data from a 1988 survey of Hubei Province, we test this possibility by comparing nonmigrants, permanent migrants, and temporary migrants. While changing family planning policies have a strong impact on timing of first birth and on the likelihood of higher-order births, migrants generally do not have more children than nonmigrants. In fact, migration tends to lower the propensity to have a child. More specifically, the fertility of temporary migrants does not differ significantly from that of other women.     

The formal dynamics of controlled populations and the echo,the boom and the bust

This paper analyzes the pattern of fluctuations of births in an age-structured population whose growth is subject to environmental or economic constraint. It synthesizes the traditional demographic analysis of age-structured renewal with constant vital rates and the economic analysis which treats population change endogenously. When cohort fertility depends on relative cohort size, or when period fertility depends on labor force size, fluctuations of forty or more years replace the traditional "echo" or generation-length cycle. Twentieth-century U. S. fertility change agrees well with the theory, as the "Easterlin Hypothesis" suggests; but the period model fits better than the cohort model.     

灾难事件对生育率的影响：历史经验与现实思考

纵观人类历史,任何一次重大灾难事件都会导致生育率波动变化。灾难事件周期与生育率变动的一般规律为:生育率在灾难事件发生短期内会受挫下降,灾难事件恢复中期内回升反弹,灾后长周期内则回归灾难事件前的变动大趋势。从外在因素的影响看,灾难事件范围越广,波及人口越多且致死率越高,生育率波动越剧烈,疫情和与环境有关的灾难事件可能会对生育能力产生负面影响。从内在因素的影响看,灾害发生地的经济发展水平、教育水平与家庭经济能力、人口年龄结构以及政府的应对能力等会影响生育率波动幅度,但不会改变波动方向。通过影响机制分析,初步观察新冠肺炎疫情所造成的生育率下降是高死亡数量带来的心理冲击、经济衰退、停工停产以及对未来生活预期不明朗和信心减弱综合作用的结果。     

Some effects of spouse separation on fertility

Simple probability models incorporating an approximation first demonstrated by Menken (1979) are used to study births averted by two classes of temporary spouse separation, single and cyclic, under conditions of natural fertility. For either class of spouse separation, births averted increases disproportionately with longer separation. For a given length of separation, births prevented are more sensitive to change in length of anovulation than to change in level ofnatural fecundability or risk of spontaneous abortion. In addition, by means of the macrosimulation model REPMOD (Bongaarts, 1977), it is shown that the fertility impact of temporary spouse separation tends to decrease as couples age.     

The TFR and birth control]

Total fertility rate if (TFR) is a simple an straight forward measure of women's fertility. However, it is difficult to use the TFR as a target measure in FP programs. If TFR level is set as a target for a particular year, how can women's fertility be regulated to achieve this target? The following analysis suggests a simple model to control the proportion of birth parity. First, the TFR is decomposed into a parity- specific TFR. The parity-specific TFR can be worked out using coefficients of the regression models calculated from data of previous fertility surveys. Once the TFR is given, the parity-specific total fertility can be calculated using a model with coefficients from empirical data. Then the number of births of each parity may be calculated from the parity-specific TFR using the female age structure in a particular year, the survival probability, and the standard fertility model for each parity. When the number of surviving children of each women at child-bearing age is known, the desired proportion of births of each parity can be calculated using the standard birth probability during a years. From these models, it would be possible to calculate how many women can have their first child/year, and how many can have the second. Thus, family planning organizations would be in a position to formulate a birth quota on the basis of the above information.