Assisted reproductive technologies (ART) in a model of fertility choice

We examine the relationship between assisted reproductive technologies (ART) and the microeconomics of fertility choice. Along the way, we develop a model consistent with between-country differences in overall fertility and fertility timing. Our analysis of ART centers around the distinction between biomedical and behavioral effects. While improvements in ART have the biomedical effect of raising fertility, they may cause some women who would otherwise have tried to have children earlier on in life to postpone childbirth to later in life when the conception success probability is lower. This behavioral effect of postponement may reduce the fertility rate.     

The Contribution of Assisted Reproduction to Completed Fertility: An Analysis of Danish Data

Assisted reproduction has a minor but increasing influence on childbearing trends in advanced societies. In Denmark, the use of assisted reproduction technology (ART) has become particularly widespread. At the same time, Danish women born in the late 1950s and the 1960s experienced stabilization or even a slight increase in their mean number of children. Broad availability and widespread use of assisted reproduction may become important factors contributing to maintaining relatively high completed fertility among the younger cohorts of Danish women. To explore this idea, we analyze and project cohort trends in fertility rates among native Danish women born in 1960‐78 and examine the likely contribution of assisted reproduction to these trends. The projected proportion of children born after ART treatment shows a substantial increase from 2.1 percent among women born in 1965 to 4‐5 percent among women born in 1978, with an estimated net impact of ART (as compared with the hypothetical situation where no ART treatment was available) on the order of 3‐4 percent. When intrauterine inseminations are included, this implies that up to 7 percent of children of those native Danish women born in 1975 and later will likely be conceived by infertility treatment.     

Policy responses to low fertility and its consequences: A global survey

Fertility at or below replacement level now characterizes 64 countries with populations totalling 44 per cent of that of the world. Many of these countries have total fertility rates below 1.5 and some have recorded below-replacement fertility for decades. It appears likely that some countries will eventually adopt policies aimed at raising fertility. Accordingly, the paper examines the effect of past policies of this type, and briefly looks to the future.     

Future low fertility prospects in Mongolia? An evaluation of the factors that support having a child

With 2.59 children per woman in 2008, Mongolia appears today as an exception in East Asia where fertility rates are far below the replacement level. Moreover, from its historical nadir of 1.95 children per women in 2005, fertility is on the rise. This paper first presents recent fertility development in Mongolia. Second, based on the experiences of European and East Asian countries, factors contributing to the development of low fertility are discussed in reference to the Mongolian context. Most of these factors are indeed found in Mongolia and could probably contribute to reducing fertility in the future. However, the country also presents cultural-family practices and recently-adopted fertility-family incentives which may support and stabilize fertility rates. These recent fertility-incentives factors and policies adopted by the Government of Mongolia are discussed in the final part from the perspective of equity, efficiency, and efficacy proposed by McDonald (2006b, “An assessment of policies that support having children from the perspectives of equity, efficiency and efficacy”, Vienna Yearbook of Population Research 2006, Special issue on ‘Postponement of childbearing on Europe’, 213–234). The aim is to determine if these measures are efficient to counterbalance and cancel out the depressing fertility effects.     

The use of traditional and modern methods of fertility control in Kinshasa, Zaire

Abstract The practice of post-partum abstinence has been a long-standing tradition in many societies of tropical Africa, yet recent research suggests an erosion of the taboo on post-partum sexual relations as a means of fertility control. The current study among women in the lower income groups in Kinshasa, Zaire, provides evidence of this. There is strong motivation toward child-spacing, as shown by 80 per cent of the women who reported to be currently practising some means of fertility control: 73 per cent with traditional methods, only 7 per cent with modern contraceptives. There appears to be some carry-over of traditional practice, in that abstinence is related to the age and nursing status of the last born child. However, the most widely practised method is withdrawal. This suggests a desire on the part of this population for alternatives to abstinence, an issue with important implications for future family planning programs in Zaire.     

Aboriginal fertility: Trends and prospects

Estimates of Aboriginal fertility compiled from an analysis of 1981 and 1986 Census data on children ever borne by Aboriginal women reveal age-specific fertility rates slightly higher than those of other Australian women at ages above 25, but very much higher rates for younger women. The result is a total fertility ratio more than 50 per cent higher than in the total Australian population, with no more than slight variation between States and Territories. A differential analysis using standardized indices shows considerable differences in levels of fertility of categories of young Aboriginal women classified by education, labour force status and income, and also differences between urban and rural areas. Analysis of prospects for Aboriginal fertility levels confirms the likelihood of continuation in the downward drift in levels of fertility that has been established during the past decade. Comparison of the estimates with another recent set of estimates obtained using the own-children method shows broad conformity in levels of total fertility ratios over time, except in the most recent period, the mid-1980s. Nevertheless, the own-children estimates distort the recent trend and also the age distribution of Aboriginal fertility.     

Economic structure and fertility: A comparative analysis

This study empirically investigates the relationship between the economic structure of populations and their level of fertility, using data from censuses recently conducted in some 50 nations. Findings show that high rates of female labor force participation outside the home and low rates of economic activity of children depress a society’s fertility level, as measured by the crude birth rate or the child-woman ratio. It is also hypothesized, but not confirmed, that the per cent of unpaid family workers in a society is positively related to its fertility level. A model is presented that treats these three components of economic structure as intervening variables through which the exogenous variables, urbanization, industrialization, and education, operate in influencing the fertility level of a society.     

Latest-Late Fertility? Decline and Resurgence of Late Parenthood Across the Low-Fertility Countries

After decades of fertility postponement, we investigate recent changes in late parenthood across low-fertility countries in the light of observations from the past. We use long series of age-specific fertility rates from the Human Fertility Database (1950–2016) for women, and new data covering the period 1990–2016 for men. In 1950, the contribution of births at age 40 and over to female fertility rates ranged from 2.5 to 9 percent, but then fell sharply until the 1980s. From the 1990s, however, the prevalence of late first births increased rapidly, especially so in countries where it was initially lowest. This has produced a late fertility rebound in the last two decades, occurring much faster for women than for men. Comparisons between recent and past extremely late (age 48+) fertility levels confirm that people are now challenging the natural fertility barriers, particularly for a first child.     

A Cohort Model of Fertility Postponement

We introduce a new formal model in which demographic behavior such as fertility is postponed by differing amounts depending only on cohort membership. The cohort-based model shows the effects of cohort shifts on period fertility measures and provides an accompanying tempo adjustment to determine the period fertility that would have occurred without postponement. Cohort-based postponement spans multiple periods and produces “fertility momentum,” with implications for future fertility rates. We illustrate several methods for model estimation and apply the model to fertility in several countries. We also compare the fit of period-based and cohort-based shift models to the recent Dutch fertility surface, showing how cohort- and period-based postponement can occur simultaneously.     

The contribution of HIV to fertility decline in rural Zimbabwe, 1985-2000

HIV-related sub-fertility has been reported for those populations in sub-Saharan Africa in which contraceptive use is low. We use data from a retrospective survey in rural Zimbabwe and multivariate logistic regression models to show that recent birth rates and current pregnancy rates are also lower among HIV-positive women than among HIV-negative women in those African populations where contraceptive use is high. The fertility reduction is smaller than where contraceptive use is low because age at first sexual intercourse is later and birth rates at older ages are already low. Nevertheless, total fertility is approximately 8.5 per cent lower and HIV-associated sub-fertility may account for as much as one-quarter of fertility decline in Zimbabwe since the late 1980s. Mechanisms for HIV-associated sub-fertility in rural Zimbabwe include more frequent widowhood and divorce, reduced coital frequency, increased amenorrhoea, and possibly, pelvic inflammatory disease. Miscarriage appears to be a less important factor than elsewhere possibly because syphilis is rare.     

Translation Formulae for Non-repeatable Events

China's one-per-hundred population survey, conducted in mid-1987, provides the first nation-level data with which to study recent fertility change in China. Using a recently developed extension of the ‘own-children’ method of fertility estimation, period parity progression ratios are computed from the survey data. Comparison with similar statistics computed from the 1982 one-per-thousand fertility survey provides a rigorous check on the quality of the results. The level of fertility so measured rose by 13 per cent between 1985 and 1987, compared with an increase of eight per cent in conventional total fertility ratios. Nearly 90 per cent of the increase was due to rising levels of progression from first to second birth. There can be little doubt that this, in turn, was due to a relaxation in the one-child family policy. Overall levels of progression to births of higher orders have been declining since 1982, but the evidence suggests that this is so only because of stringent government efforts to control births of third and higher orders.     

A model of numbers of births in three countries,with persistent forty-year cycles

This paper describes a model which relates fertility to partner availability, an aspect of relative cohort size. Partner availability is affected by the tendency for males to reproduce at a later age than females. For women born at a time of rising birth rates, there is a shortage of slightly older men as potential partners. Women born when birthrates are falling enjoy a surplus of older men from which to choose. This model is believed to be the first non-linear demographic feedback model involving feedbacks through marriage squeezes in which empirically estimated values of the parameters imply persistent limit cycles. The deterministic model makes births in each five-year period a function of births in previous five-year periods. The form of the function is chosen to model the effect of partner availability upon entry into reproductive relationships, and therefore on age-specific fertility. Marriage rates are not modeled directly. The model was developed from data for more than a century from England and Wales, New Zealand, and the US. The demographic transition is modeled with a logistic function and age-specific fertility rates are estimated using lognormal distributions. The stepwise inclusion of a partner availability estimate in the model showed that it accounts for 29% of otherwise unexplained variance. Projected future births stabilize in sustained or limit cycles with periods a little longer than 40 years, and amplitudes of at least 7% of the mean. The necessary conditions for cycle persistence are outlined on a graph of maximum and minimum fertility parameters.     

A lost family-planning regime in eighteenth-century Ceylon

Based on Dutch colonial registers (thombos), this paper reconstructs fertility for two districts in Ceylon, 1756–68. It overcomes challenges in data quality by establishing the outer bounds of plausible estimates in a series of scenarios. Among these, total fertility rates (TFRs) averaged 5.5 in one district, but only 2.7 in the other. These figures exclude the victims of infanticide, a custom noted in European travelogues between about 1660 and 1820. Sex ratios among children differed depending on the number of older siblings, and overall, 27?per cent of girls are missing in one district and 57?per cent in the other. There was little significant variation either in the TFR or the sex ratio by socio-economic status, suggesting that poverty was not a key factor in motivating infanticides. Instead, we argue that at least parts of Ceylon had a forward-looking culture of family planning in the eighteenth century, which was lost in subsequent decades.     

Evolving Fertility Goals and Behaviors in Current U.S. Childbearing Cohorts

In the post-Recession era, U.S. fertility rates have continued to fall. It is unclear if these declines are driven by shifts in fertility goals or growing difficulty in achieving goals. In this paper, we construct synthetic cohorts of men and women to examine both cross-cohort and within-cohort changes in fertility goals using multiple cycles of the National Survey of Family Growth. Although more recent cohorts exhibit lower achieved fertility at younger ages than earlier cohorts at the same age, intended parity remains around two children, and intentions to remain childless rarely exceed 15 percent. There is weak evidence of a growing fertility gap in the early 30s, suggesting more recent cohorts will need considerable childbearing in the 30s and early 40s to “catch up” to earlier goals, yet low-parity women in their early 40s are decreasingly likely to have unfulfilled fertility desires or intentions to have children. Low-parity men in their early 40s, though, are increasingly likely to intend children. Declines in U.S. fertility thus seem to be largely driven not by changes in early-life fertility goals so much as either a decreasing likelihood of achieving earlier goals or, perhaps, shifts in the preferred timing of fertility that depress period measures.     

China’s Demographic Future Under the New Two-Child Policy

China implemented the two-child policy in 2016, however, potential impacts of this new policy on its population reality have not been adequately understood. Using population census data and 1% population sampling data during the period of 1982–2015, this study develops a fertility simulation model to explore the effects of the two-child policy on women’s total fertility rate, and employs Cohort Component Method in population projections to examine China’s demographic future with different fertility regimes. The fertility simulation results reveal that the two-child policy will make significantly positive effects on China’s total fertility rate through increasing second births, leading to a sharp but temporary increase in the first 5 years after the implementation of the new policy. In addition, population projections using simulated total fertility rates show that the Chinese population would reach its peak value around the middle 2020s and be faced with the reduction of labor force supply and rapid aging process, featured with remarkable increases in both size and share of the elderly population. The findings suggest that the two-child policy would undoubtedly affect China’s fertility rates and demographic future; however, the effects are mild and temporary.

     

American political affiliation, 2003-43: a cohort component projection

The recent rise in identification with American political parties has focused interest on the long-term dynamics of party support. Liberal commentators cite immigration and youth as forces that will produce a natural advantage for the Democrats in the future, while conservative writers highlight the importance of high fertility amongst Republicans in securing growth. These opinions are not based on demographic analysis. We addressed this omission by undertaking the first ever cohort component projection (up to 2043) of populations by American party allegiance, based on survey and census data. On current trends, we predict that American partisanship will change much less than the nation's ethnic composition because the parties are similar in age structure. Nevertheless, our projections suggest that the Democrats will gain 2-3 per cent more support than the Republicans by 2043, mainly through immigration, although the higher fertility of Republicans may eventually offset that advantage.     

Vital rates in India 1961-71 estimated from 1971 census data

Abstract In the last decade the increase in the population of India, while, of course, very large, was smaller than predicted by official forecasts. With the use of recent census and sample registration data - in the absence of age-specific rates and adequate vital statistics - this paper provides estimates of fertility and mortality through the reverse-survival and forward-projection methods. Birth rates are estimated as 40·5-42, death rates as 18-20, and life expectancy at birth as 45-46 years. Mortality decline had been smaller than forecast but more than during any comparable period in the past, even though current mortality levels, particularly infant mortality, are still high. Males continue to have a longer life expectation than females, with a difference that has widened in the past decade. The decline of between seven and ten per cent in the crude birth rate is largely due to changes in marital fertility and to some extent to changes in age and marital composition. Because of greater decline in death rates than birth rates, the 1961-71 decade shows a higher rate of population growth than previous periods.     

Population dynamics in Germany: the role of immigration and population momentum

The effects of changes in rates of mortality, fertility, and migration depend not only on the age-specific patterns and levels of these rates, but on the age structure of the population. In order to remove the influences of the age structure and concentrate on the effects of the demographic rates themselves, a common practice is to analyze the influences of the rates for a standard age structure. This paper analyzes current and future population changes in Germany, using a stationary population equivalent model (SPE) that shows long-term effects of current fertility, mortality, and international migration patterns. Results indicate that the German population will eventually decline because of below replacement fertility, if net immigration does not counteract this decrease. This means, for instance, that the long-term stationary population levels for Germany will decrease by approximately 6.5 million during a decade in which current fertility, mortality, and international migration levels prevail. The paper also reports how various other assumptions for mortality, fertility, and international migration affect the SPE model for Germany.     

The effects of child-related benefits and pensions on fertility by birth order: A test on Hungarian data

Using aggregate time-series data from post-war Hungary, we investigated the effect of child-related benefits and pensions on overall fertility and fertility by birth order. The results indicate moderate effects that are robust across a wide range of specifications. According to our estimates, a 1-per-cent increase in child-related benefits would increase total fertility by 0.2 per cent, while the same increase in pensions would decrease fertility by 0.2 per cent. The magnitude of both effects increases by birth order; this is more robust for child-related benefits.     

The End of the Fertility Transition in the Developed World

By the late 1990s the average period total fertility rate in the developed world had declined to 1.6, a level substantially lower than projected in the 1970s and 1980s. This article examines recent trends and patterns in fertility in the developed world with particular emphasis on the effects and implications of changes in the timing of childbearing. The main objective is to demonstrate that while fertility in these countries is indeed low, women's childbearing levels are not as low as period measures such as the total fertility rate suggest. To obtain a full understanding of the various dimensions of fertility change. several indicators are examined, including period and cohort fertility by birth order and childbearing preferences. An analysis of these indicators demonstrates that period fertility measures in many developed countries are temporarily depressed by a rise in the mean age at childbearing. The distortion of the TFR is as great as 0.4 births per woman in Italy and Spain. These effects have been present in many developed countries since the 1970s and could continue for years into the future. But tempo effects are temporary, and once the postponement of childbearing ends—as it eventually must—the corresponding fertility‐depressing effect stops, thus putting upward pressure on period fertility. Countries with very low fertility and substantial tempo effects may well experience rises in fertility in the near future if the timing of childbearing stabilizes. Even if this happens, however, it seems unlikely that fertility will rebound to the replacement level.