Baby boomers
Unpacking the “Black Box” of Race–Ethnic Variation in Fertility
Karen Benjamin Guzzo et al.
Race and Social Problems, June 2015, Pages 135-149
Abstract:
Race–ethnic differences in a range of childbearing behaviors are long standing and well documented, and these differences are attenuated, but not eliminated, when accounting for socioeconomic disparities. The residual differences are often attributed to vague and untested variation across race–ethnic groups in knowledge, attitudes, psychological attributes, normative beliefs, and social context. We use the longitudinal Toledo Adolescent Relationship Study (TARS), which contains a rich set of such factors measured in early adolescence, to assess whether they contribute to race–ethnic differences in having a birth among men and women ages 17–24 (n = 1,042). Specifically, we test whether individual attitudes, religiosity, and academic behaviors; knowledge and behaviors regarding sex and dating; peer normative context; and parental communication about sex account for variation in the risk of an early birth. We find that socioeconomic factors attenuate but do not reduce differences between black, Hispanic, and white respondents. Including adolescent academic performance and early entry into sex reduces the black–white difference in the odds of early fertility to non-significance; however, beyond socioeconomic status, none of the broad range of factors further attenuate Hispanic–white differences, which remain large and statistically significant.
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Can't Afford a Baby? Debt and Young Americans
Michael Nau, Rachel Dwyer & Randy Hodson
Research in Social Stratification and Mobility, forthcoming
Abstract:
This article explores the role of personal debt in the transition to parenthood. We analyze data from the National Longitudinal Study of Youth-1997 cohort and find that for the generation coming of age in the 2000s, student loans delay fertility for women, particularly at very high levels of debt. Home mortgages and credit card debt, in contrast, appear to be precursors to parenthood. These results indicate that different forms of debt have different implications for early adulthood transitions: whereas consumer loans or home mortgages immediately increase access to consumption goods, there is often a significant delay between the accrual and realization of benefits for student loans. The double-edged nature of debt as both barrier and facilitator to life transitions highlights the importance of looking at debt both as a monetary issue and also as a carrier of social meanings.
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Black-White Differences in Attitudes Related to Pregnancy Among Young Women
Jennifer Barber, Jennifer Eckerman Yarger & Heather Gatny
Demography, June 2015, Pages 751-786
Abstract:
In this article, we use newly available data from the Relationship Dynamics and Social Life (RDSL) study to compare a wide range of attitudes related to pregnancy for 961 black and white young women. We also investigate the extent to which race differences are mediated by, or net of, family background, childhood socioeconomic status (SES), adolescent experiences related to pregnancy, and current SES. Compared with white women, black women generally have less positive attitudes toward young nonmarital sex, contraception, and childbearing, and have less desire for sex in the upcoming year. This is largely because black women are more religious than white women and partly because they are more socioeconomically disadvantaged in young adulthood. However, in spite of these less positive attitudes, black women are more likely to expect sex without contraception in the next year and to expect more positive consequences if they were to become pregnant, relative to white women. This is largely because, relative to white women, black women had higher rates of sex without contraception in adolescence and partly because they are more likely to have grown up with a single parent. It is unclear whether attitudes toward contraception and pregnancy preceded or are a consequence of adolescent sex without contraception. Some race differences remain unexplained; net of all potential mediators in our models, black women have less desire for sex in the upcoming year, but they are less willing to refuse to have sex with a partner if they think it would make him angry and they expect more positive personal consequences of a pregnancy, relative to white women. In spite of these differences, black women’s desires to achieve and to prevent pregnancy are very similar to white women’s desires.
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Offline Effects of Online Connecting: The Impact of Broadband Diffusion on Teen Fertility Decisions
Melanie Guldi & Chris Herbst
Arizona State University Working Paper, May 2015
Abstract:
Broadband (high-speed) internet access expanded rapidly from 1999 to 2007. This expansion is associated with higher economic growth and labor market activity. In this paper, we examine whether the rollout also affected the social connections teens make. Specifically, we look at the relationship between increased broadband access and teen fertility. We hypothesize that increasing access to high-speed internet can influence fertility decisions by changing the size of the market as well as increasing the information available to participants in the market. We seek to understand both the overall effect of broadband internet on teen fertility as well as the mechanisms underlying this effect. Our results suggest that increased broadband access explains at least thirteen percent of the decline in the teen birth rate between 1999 and 2007. Although we focus on social markets, this work contributes more broadly to an understanding of how new technology interacts with existing markets.
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Ancestry Matters: Patrilineage Growth and Extinction
Xi Song, Cameron Campbell & James Lee
American Sociological Review, June 2015, Pages 574-602
Abstract:
Patrilineality, the organization of kinship, inheritance, and other key social processes based on patrilineal male descent, has been a salient feature of social organization in China and many other societies for centuries. Because patrilineage continuity or growth was the central focus of reproductive strategies in such societies, we introduce the number of patrilineal male descendants generations later as a stratification outcome. By reconstructing and analyzing 20,000 patrilineages in two prospective, multi-generational population databases from eighteenth- and nineteenth-century China, we show that patrilineages founded by high-status males had higher growth rates for the next 150 years. The elevated growth rate of these patrilineages was due more to their having a lower probability of extinction at each point in time than to surviving patrilineal male descendants having larger numbers of sons on average. As a result, male descendants of high-status males account for a disproportionately large share of the male population in later generations. In China and elsewhere, patrilineal kin network characteristics influence individuals’ life chances; effects of a male founder’s characteristics on patrilineage size many generations later thus represent an indirect channel of status transmission that has not been considered previously.
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Xiaoling Lim Ang
Journal of Family and Economic Issues, June 2015, Pages 263-288
Abstract:
This paper examined the labor supply and fertility effects of fertility incentives by making use of two major policy changes that occurred in Canada over the past 25 years: the Quebec Parental Insurance Program which provided generous parental leave benefits, and the series of cash-transfer fertility incentives introduced in Quebec in the 1980s. The empirical work for these projects was conducted using confidential versions of the Canadian Census and the Labour Force Surveys on-site at Statistics Canada. I found that while increases in the generosity of parental leave benefits substantially increased the birth rate and induced increases in labor supply among women of childbearing age, cash-transfer fertility incentives only slightly increased birth rates and decreased female labor supply. The net government cost of each additional birth due to an increase in the generosity of parental leave programs was $15,828 in 2008 Canadian dollars, whereas the net government cost of an additional birth due to cash-transfer fertility incentives was $223,625 in 2008 Canadian dollars. Therefore, paid parental leave is a low-cost way to increase fertility whereas the price per additional birth due to cash-transfer fertility incentives is quite high.
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Jukka Savolainen et al.
Youth & Society, July 2015, Pages 520-538
Abstract:
There are strong reasons to assume that early onset of puberty accelerates coital debut among adolescent girls. Although many studies support this assumption, evidence regarding the putative causal processes is limited and inconclusive. In this research, longitudinal data from the 1986 Northern Finland Birth Cohort Study (N = 2,596) were used to address three theoretical explanations: (a) a direct effect premised on biological processes, (b) a mediated path based on social psychological processes, and (c) a spurious effect derived from the evolutionary theory of socialization. In support of the social psychological pathway, the negative association between age at menarche and coital status at age 15 was almost fully mediated by differential social exposure — an empirical construct measuring involvement in high-risk social contexts.
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How Many More Missing Women? Excess Female Mortality and Prenatal Sex Selection, 1970–2050
John Bongaarts & Christophe Guilmoto
Population and Development Review, June 2015, Pages 241–269
Abstract:
Sex-based discrimination has resulted in severe demographic imbalances between males and females, culminating in a large number of “missing women” in several countries around the world. We provide new estimates and projections of the number of missing females and of the roles played by prenatal and postnatal factors in this imbalance. We estimate time series of the number of missing females, the number of excess female deaths, and the number of missing female births for the world and selected countries. Estimates are provided for 1970–2010 and projections are made from 2010 to 2050. We show that the estimates of these different indicators are consistent with one another and account for the dynamics of the population of missing females over time. We conclude that the number of missing females has steadily risen in the past decades, reaching 126 million in 2010, and the number is expected to peak at 150 million in 2035. Excess mortality was the dominant cause of missing females in the past, and this is expected to remain the case in future decades in spite of the recent rise of prenatal sex selection. The annual number of newly missing females reached 3.4 million in 2010 and is expected to remain above 3 million every year until 2050.
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State Abortion Context and U.S. Women's Contraceptive Choices, 1995–2010
Josephine Jacobs & Maria Stanfors
Perspectives on Sexual and Reproductive Health, June 2015, Pages 71–82
Context: The number of women in the United States exposed to restrictive abortion policies has increased substantially over the past decade. It is not well understood whether and how women adjust their contraceptive behavior when faced with restrictive abortion contexts.
Methods: Data from 14,523 women aged 15–44 were drawn from the 1995 and 2010 cycles of the National Survey of Family Growth. A difference-in-differences approach was employed to examine the relationship between state-level changes in women's access to abortion and their contraceptive choices. Multinomial logistic regression analysis was used to determine the relative risk of using highly effective or less effective methods rather than no method for women exposed to varying levels of restrictive abortion contexts.
Results: Women who lived in a state where abortion access was low were more likely than women living in a state with greater access to use highly effective contraceptives rather than no method (relative risk ratio, 1.4). Similarly, women in states characterized by high abortion hostility (i.e., states with four or more types of restrictive policies in place) were more likely to use highly effective methods than were women in states with less hostility (1.3). The transition to a more restrictive abortion context was not associated with women's contraceptive behavior, perhaps because states that introduced restrictive abortion legislation between 1995 and 2010 already had significant limitations in place.
Conclusions: To prevent unwanted pregnancies, it is important to ensure access to highly effective contraceptive methods when access to abortions is limited.
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The Labor Supply Effects of Delayed First Birth
Jane Leber Herr
American Economic Review, May 2015, Pages 630-637
Abstract:
In this paper I compare the relationship between first-birth timing and post-birth labor supply for high school and college graduate mothers. Given that pre-birth wages are increasing in fertility delay, the rising opportunity cost of time would suggest that among both groups, later mothers work more. Yet I only find this pattern for high school graduates. For college graduates, I instead find that there is a strong U-shaped pattern between hours worked within motherhood, and the career timing of first birth.
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Does natural selection favour taller stature among the tallest people on earth?
Gert Stulp et al.
Proceedings of the Royal Society: Biological Sciences, 7 May 2015
Abstract:
The Dutch are the tallest people on earth. Over the last 200 years, they have grown 20 cm in height: a rapid rate of increase that points to environmental causes. This secular trend in height is echoed across all Western populations, but came to an end, or at least levelled off, much earlier than in The Netherlands. One possibility, then, is that natural selection acted congruently with these environmentally induced changes to further promote tall stature among the people of the lowlands. Using data from the LifeLines study, which follows a large sample of the population of the north of The Netherlands (n = 94 516), we examined how height was related to measures of reproductive success (as a proxy for fitness). Across three decades (1935–1967), height was consistently related to reproductive output (number of children born and number of surviving children), favouring taller men and average height women. This was despite a later age at first birth for taller individuals. Furthermore, even in this low-mortality population, taller women experienced higher child survival, which contributed positively to their increased reproductive success. Thus, natural selection in addition to good environmental conditions may help explain why the Dutch are so tall.
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How Much Can Expanding Access to Long-Acting Reversible Contraceptives Reduce Teen Birth Rates?
Jason Lindo & Analisa Packham
NBER Working Paper, June 2015
Abstract:
Despite a near-continuous decline over the past 20 years, the teen birth rate in the United States continues to be higher than that of other developed countries. Given that over three- quarters of teen births are unintended at conception and that over a third of unplanned births are to women using contraception, many have advocated for promoting the use of long-acting reversible contraceptives (LARCs), which are more effective at preventing pregnancy than more commonly used contraceptives. In order to speak to the degree to which increasing access to LARCs can reduce teen birth rates, this paper analyzes the first large-scale policy intervention to promote and improve access to LARCs in the United States: Colorado’s Family Planning Initiative. We estimate its effects using a difference-in-differences approach, comparing the changes in teen birth rates in Colorado counties with Title X clinics (which received funding) to the changes observed in other US counties with Title X clinics. The results of this analysis indicate that the $23 million program reduced the teen birth rate by approximately 5% in the four years following its implementation, providing support for the notion that increasing access to LARCs is a mechanism through which policy can reduce teenage childbearing.
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Repeat Abortions in New York City, 2010
Amita Toprani
Journal of Urban Health, June 2015, Pages 593-603
Abstract:
This study aims to describe factors associated with the number of past abortions obtained by New York City (NYC) abortion patients in 2010. We calculated rates of first and repeat abortion by age, race/ethnicity, and neighborhood-level poverty and the mean number of self-reported past abortions by age, race/ethnicity, neighborhood-level poverty, number of living children, education, payment method, marital status, and nativity. We used negative binomial regression to predict number of past abortions by patient characteristics. Of the 76,614 abortions reported for NYC residents in 2010, 57 % were repeat abortions. Repeat abortions comprised >50 % of total abortions among the majority of sociodemographic groups we examined. Overall, mean number of past abortions was 1.3. Mean number of past abortions was higher for women aged 30–34 years (1.77), women with ≥5 children (2.50), and black non-Hispanic women (1.52). After multivariable regression, age, race/ethnicity, and number of children were the strongest predictors of number of past abortions. This analysis demonstrates that, although socioeconomic disparities exist, all abortion patients are at high risk for repeat unintended pregnancy and abortion.
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Cary Lou & Adam Thomas
Perspectives on Sexual and Reproductive Health, June 2015, Pages 91–98
Context: Females who do well in school are less likely than those who do poorly to experience a nonmarital teenage birth. However, little is known about which dimensions of academic achievement are the most strongly related to teenage childbearing, or about whether the relationship between achievement and childbearing varies according to the presence of other behavioral problems.
Methods: Individual-level and family-level data from the Panel Study of Income Dynamics, combined with information on contextual state-level economic and policy measures, were used to study nonmarital childbearing between the ages of 16 and 19 among 701 females who turned 16 between 2000 and 2007. Multivariate logistic regression analyses examined the relationship between the probability of nonmarital teenage childbearing and age-standardized scores on academic assessments of letter-word identification, passage comprehension and applied problem-solving ability.
Results: Scores on the passage comprehension and applied problem-solving subtests were strongly associated with the probability of experiencing a nonmarital teenage birth among respondents who had relatively few behavioral problems. For this group, an increase of one standard deviation in the score on either assessment was associated with a reduction of about 50% in the risk of experiencing a nonmarital teenage birth. However, no evidence was found of an equivalent relationship among respondents with more pronounced behavioral problems or for the letter-word identification assessment.
Conclusions: Future research should continue to explore the possibility that improvements in academic achievement may help to reduce the rate of nonmarital teenage childbearing.
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Fitness Consequences of Advanced Ancestral Age over Three Generations in Humans
Adam Hayward, Virpi Lummaa & Georgii Bazykin
PLoS ONE, June 2015
Abstract:
A rapid rise in age at parenthood in contemporary societies has increased interest in reports of higher prevalence of de novo mutations and health problems in individuals with older fathers, but the fitness consequences of such age effects over several generations remain untested. Here, we use extensive pedigree data on seven pre-industrial Finnish populations to show how the ages of ancestors for up to three generations are associated with fitness traits. Individuals whose fathers, grandfathers and great-grandfathers fathered their lineage on average under age 30 were ~13% more likely to survive to adulthood than those whose ancestors fathered their lineage at over 40 years. In addition, females had a lower probability of marriage if their male ancestors were older. These findings are consistent with an increase of the number of accumulated de novo mutations with male age, suggesting that deleterious mutations acquired from recent ancestors may be a substantial burden to fitness in humans. However, possible non-mutational explanations for the observed associations are also discussed.
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Selection criteria in the search for a sperm donor: Behavioural traits versus physical appearance
Stephen Whyte & Benno Torgler
Journal of Bioeconomics, July 2015, Pages 151-171
Abstract:
Despite extensive literature on female mate choice, empirical evidence on women’s mating preferences in the search for a sperm donor is scarce, even though this search, by isolating a male’s genetic impact on offspring from other factors like paternal investment, offers a naturally ”controlled” research setting. In this paper, we work to fill this void by examining the rapidly growing online sperm donor market, which is raising new challenges by offering women novel ways to seek out donor sperm. We not only identify individual factors that influence women’s mating preferences but find strong support for the proposition that behavioural traits (inner values) are more important in these choices than physical appearance (exterior values). We also report evidence that physical factors matter more than resources or other external cues of material success, perhaps because the relevance of good character in donor selection is part of a female psychological adaptation throughout evolutionary history. The lack of evidence on a preference for material resources, on the other hand, may indicate the ability of peer socialization and better access to resources to rapidly shape the female decision process. Overall, the paper makes useful contributions to both the literature on human behaviour and that on decision-making in extreme and highly important situations.
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Woman's body symmetry and oxidative stress in the first trimester of pregnancy
Agnieszka Żelaźniewicz, Judyta Nowak & Bogusław Pawłowski
American Journal of Human Biology, forthcoming
Objectives: High level of oxidative stress (OS) during the first weeks of pregnancy is related to many serious pregnancy complications. Previous studies showed that body fluctuating asymmetry (FA) is related to OS level in men, suggesting that FA is a marker of oxidative balance in an individual. The aim of this study was to analyze if body FA was related to the level of biomarkers of OS in the first trimester of pregnancy.
Methods: The sample included 34 women in the first trimester of pregnancy, not smoking, and not exposed to toxins in their work environment. The composite FA and levels of two biomarkers of OS, 8-iso-ProstaglandinF2α (an indicator of oxidative damage to lipids) and 8-OH-dG (an indicator of oxidative damage to DNA) were measured. Factors that may affect the level of OS (vitamin supplementation, age, smoking, alcohol drinking, physical activity, and health condition) were controlled.
Results: The levels of OS markers in the first trimester of pregnancy correlated positively with women's FA (r = 0.52, P = 0.002 for 8-OH-dG; r = 0.50; P = 0.003 for 8-iso-PGF2α level) and positively with body height (r = 0.37, P = 0.03 for 8-OH-dG level).
Conclusion: The level of OS is likely to be a substantial and important fitness trait, and FA may convey information on the level of OS in women. The result confirms that FA is an indicator of biological condition, as suggested by an evolutionary approach to morphological human traits perceived as attractive.