Making babies
Ted Joyce, Ruoding Tan & Yuxiu Zhangc
Journal of Health Economics, forthcoming
Abstract:
We use unique data on abortions performed in New York State from 1971-1975 to demonstrate that women travelled hundreds of miles for a legal abortion before Roe. A 100-mile increase in distance for women who live approximately 183 miles from New York was associated with a decline in abortion rates of 12.2 percent whereas the same change for women who lived 830 miles from New York lowered abortion rates by 3.3 percent. The abortion rates of nonwhites were more sensitive to distance than those of whites. We found a positive and robust association between distance to the nearest abortion provider and teen birth rates but less consistent estimates for other ages. Our results suggest that even if some states lost all abortion providers due to legislative policies, the impact on population measures of birth and abortion rates would be small as most women would travel to states with abortion services.
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Community-Wide Job Loss and Teenage Fertility
Elizabeth Ananat, Anna Gassman-Pines & Christina Gibson-Davis
NBER Working Paper, April 2013
Abstract:
We estimate the effects of economic downturns on the birth rates of 15- to 19-year-olds, using county-level business closings and layoffs in North Carolina over 1990-2010 as a plausibly exogenous source of variation in the strength of the local economy. We find little effect of job losses on the white teen birth rate. For black teens, however, job losses to 1% of the working-age population decrease the birth rate by around 2%. Birth declines start five months after the job loss and then last for over a year. Linking the timing of job losses and conceptions suggests that black teen births decline due to increased terminations and perhaps also changes in pre-pregnancy behaviors; national data on risk behaviors also provide evidence that black teens reduce sexual activity and increase contraception use in response to job losses. Job losses seven to nine months after conception do not affect teen birth rates, indicating that teens do not anticipate job losses and lending confidence that job losses are "shocks" that can be viewed as quasi-experimental variation. We also find evidence that relatively advantaged black teens disproportionately abort after job losses, implying that the average child born to a black teen in the wake of job loss is relatively more disadvantaged.
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Sex Ratios and Crime: Evidence from China
Lena Edlund et al.
Review of Economics and Statistics, forthcoming
Abstract:
Since the introduction of the One-Child policy in China in 1979, abnormally many boys to girls have been born, foreshadowing a sizeable bride shortage. What do young men unable to find wives do? This paper focuses on criminality, an asocial activity that has seen a marked rise since the mid-1990s. Exploiting province-year level variation, we find an elasticity of crime with respect to the sex ratio of 16-25 years olds of 3.4, suggesting that male sex ratios can account for 1/7th of the rise in crime. We hypothesize that adverse marriage market conditions drive the found association.
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Natural Selection in Utero: Evidence from the Great East Japan Earthquake
R. Catalano, T. Yorifuji & I. Kawachi
American Journal of Human Biology, forthcoming
Objectives: Controversy remains over whether declines in male births reported after population stressors result from either or both reduced conception of males or increased selection in utero against male fetuses. We use monthly birth cohorts to determine if Japanese male births following the Great East Japan Earthquake of 2011 fell below levels expected from female births and from history (i.e., autocorrelation) among cohorts exposed to the Earthquake at or after conception.
Methods: We apply interrupted time-series methods to 69 months (i.e., April, 2006 through December, 2011) of birth data from the most and least affected prefectures as well as from the remainder of Japan. We estimate expected male births from female births and from autocorrelation.
Results: Findings varied by distance from the greatest damage but suggest sensitive periods both early and late in gestation when population stressors may induce selection against males in utero. Support for reduced conception of males appeared only in the prefectures most damaged by the Earthquake.
Conclusions: Results align with the claim that natural selection has conserved mechanisms that reduce the odds of a male live birth during stressful times by reducing the conception of males and by increasing the rate of spontaneous abortion among male fetuses.
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Bastien Chabé-Ferret & Paolo Melindi Ghidi
Journal of Population Economics, July 2013, Pages 887-905
Abstract:
We revisit the question of why fertility behaviors and educational decisions appear to vary systematically across ethnic groups. We assess the possibility that differences in fertility across groups remain even though their socio-economic characteristics are similar. More specifically, we consider that parents' fertility decisions are affected by the uncertainty concerning the future economic status of their offspring. We assume that this uncertainty varies across groups and is linked to the size of the group one belongs to. We find theoretical support for the minority status hypothesis according to which members of large minorities usually have a higher fertility than those in the majority facing low potential for social mobility while small minorities have lower fertility.
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Understanding Measures of Nonmarital Fertility: The Roles of Marriage and Access to Human Capital
Jo Anna Gray & Joe Stone
Contemporary Economic Policy, forthcoming
Abstract:
This paper proposes an explanation for several decades of rising U.S. nonmarital birth rates and shares, and for cross-sectional differences in black-white fertility. Significantly, the explanation does not rely on changes over time or differences across races in individual fertility behavior. It is consistent with the rising nonmarital fertility measures observed in the United States since the mid-1970s, higher measured fertility for unmarried blacks than whites, and differences across races in the timing of childbearing, despite nearly constant total fertility rates and increasingly similar target family sizes for blacks and whites. The explanation relies on a selection effect associated with changes in the marriage rate and on racial differences in access to human capital investment opportunities. We find strong support for the explanation using U.S. data over the period 1957-2002. Our findings suggest caution in interpreting the results of empirical studies of childbearing that examine marital and nonmarital fertility rates separately, as these studies typically ignore the selection effect of marriage.
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Racial and Ethnic Differences in the Transition To a Teenage Birth in the United States
Jennifer Manlove et al.
Perspectives on Sexual and Reproductive Health, June 2013, Pages 89-100
Context: Rates of teenage childbearing are high in the United States, and they differ substantially by race and ethnicity and nativity status.
Methods: Data from the National Longitudinal Survey of Youth 1997 cohort were used to link characteristics of white, black, U.S.-born Hispanic and foreign-born Hispanic adolescents to teenage childbearing. Following a sample of 3,294 females aged 12-16 through age 19, discrete-time logistic regression analyses were used to examine which domains of teenagers' lives were associated with the transition to a teenage birth for each racial and ethnic group, and whether these associations help explain racial and ethnic and nativity differences in this transition.
Results: In a baseline multivariate analysis controlling for age, compared with whites, foreign-born Hispanics had more than three times the odds of a teenage birth (odds ratio, 3.5), while blacks and native-born Hispanics had about twice the odds (2.1 and 1.9, respectively). Additional controls (for family environments; individual, peer and dating characteristics; characteristics of first sexual relationships; and subsequent sexual experience) reduced the difference between blacks and whites, and between foreign-born Hispanics and whites, and eliminated the difference between U.S.-born Hispanics and whites. Further, if racial or ethnic minority adolescents had the same distribution as did white teenagers across all characteristics, the predicted probability of a teenage birth would be reduced by 40% for blacks and 35% for U.S.-born Hispanics.
Conclusions: Differences in the context of adolescence may account for a substantial portion of racial, ethnic and nativity differences in teenage childbearing.
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Employment protection and fertility: Evidence from the 1990 Italian reform
Ervin Prifti & Daniela Vuri
Labour Economics, August 2013, Pages 77-88
Abstract:
The aim of this paper is to investigate the effect of Employment Protection Legislation (EPL) on fertility decisions of Italian working women using administrative data. We exploit a reform that introduced in 1990 costs for dismissals unmotivated by a 'fair cause' or 'justified motive' in firms below 15 employees and left firing costs unchanged for bigger firms. We use this quasi-experimental setup to study the hypothesis that increased EPL reduces future job insecurity and positively affects a female worker's proneness to take childbearing decisions. We use a difference in difference (OLS-DID) model to control for possible period-invariant sorting bias and an instrumental variable (IV-DID) model to account for time-varying endogeneity of the treatment status. We find that reduced economic insecurity following a strengthening of the EPL regime has a positive and sizable effect on fertility decisions of Italian working women. This result is robust to a number of checks regarding possible interactions with other policy reforms occurring around 1990, changes in the sample of workers and firms, and use of an alternative set of exclusion restrictions.
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Alexandre Courtiol et al.
Current Biology, 20 May 2013, Pages 884-889
Abstract:
Recent human history is marked by demographic transitions characterized by declines in mortality and fertility. By influencing the variance in those fitness components, demographic transitions can affect selection on other traits. Parallel to changes in selection triggered by demography per se, relationships between fitness and anthropometric traits are also expected to change due to modification of the environment. Here we explore for the first time these two main evolutionary consequences of demographic transitions using a unique data set containing survival, fertility, and anthropometric data for thousands of women in rural Gambia from 1956-2010. We show how the demographic transition influenced directional selection on height and body mass index (BMI). We observed a change in selection for both traits mediated by variation in fertility: selection initially favored short females with high BMI values but shifted across the demographic transition to favor tall females with low BMI values. We demonstrate that these differences resulted both from changes in fitness variance that shape the strength of selection and from shifts in selective pressures triggered by environmental changes. These results suggest that demographic and environmental trends encountered by current human populations worldwide are likely to modify, but not stop, natural selection in humans.
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Maternal Stress and Infant Mortality: The Importance of the Preconception Period
Quetzal Class et al.
Psychological Science, forthcoming
Abstract:
Although preconception and prenatal maternal stress are associated with adverse outcomes in birth and childhood, their relation to infant mortality remains uncertain. We used logistic regression to study infant mortality risk following maternal stress within a population-based sample of infants born in Sweden between 1973 and 2008 (N = 3,055,361). Preconception (6-0 months before conception) and prenatal (between conception and birth) stress were defined as death of a first-degree relative of the mother. A total of 20,651 offspring were exposed to preconception stress, 26,731 offspring were exposed to prenatal stress, and 8,398 cases of infant mortality were identified. Preconception stress increased the risk of infant mortality independently of measured covariates, and this association was timing specific and robust across low-risk groups. Prenatal stress did not increase risk of infant mortality. These results suggest that the period immediately before conception may be a sensitive developmental period with ramifications for infant mortality risk.
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A model comparison approach shows stronger support for economic models of fertility decline
Mary Shenk et al.
Proceedings of the National Academy of Sciences, 14 May 2013, Pages 8045-8050
Abstract:
The demographic transition is an ongoing global phenomenon in which high fertility and mortality rates are replaced by low fertility and mortality. Despite intense interest in the causes of the transition, especially with respect to decreasing fertility rates, the underlying mechanisms motivating it are still subject to much debate. The literature is crowded with competing theories, including causal models that emphasize (i) mortality and extrinsic risk, (ii) the economic costs and benefits of investing in self and children, and (iii) the cultural transmission of low-fertility social norms. Distinguishing between models, however, requires more comprehensive, better-controlled studies than have been published to date. We use detailed demographic data from recent fieldwork to determine which models produce the most robust explanation of the rapid, recent demographic transition in rural Bangladesh. To rigorously compare models, we use an evidence-based statistical approach using model selection techniques derived from likelihood theory. This approach allows us to quantify the relative evidence the data give to alternative models, even when model predictions are not mutually exclusive. Results indicate that fertility, measured as either total fertility or surviving children, is best explained by models emphasizing economic factors and related motivations for parental investment. Our results also suggest important synergies between models, implicating multiple causal pathways in the rapidity and degree of recent demographic transitions.
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The Effect of Education on Fertility: Evidence from a Compulsory Schooling Reform
Kamila Cygan-Rehm & Miriam Maeder
Labour Economics, forthcoming
Abstract:
This paper investigates the effect of education on fertility under inflexible labor market conditions. We exploit exogenous variation from a German compulsory schooling reform to deal with the endogeneity of education. By using data from two complementary datasets, we examine different fertility outcomes over the life cycle. In contrast to evidence for other developed countries, we find that increased education causally reduces completed fertility. This negative effect operates through a postponement of first births away from teenage years and no catch-up later in life. We attribute these findings to the particularly high opportunity costs of childrearing in Germany.
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Economic Insecurity and Fertility Intentions: The Case of Italy
Francesca Modena, Concetta Rondinelli & Fabio Sabatini
Review of Income and Wealth, forthcoming
Abstract:
We aim to provide an explanation for the combination of the relatively low female participation rates and lowest-low fertility levels in Italy. Starting from the assumption that childbearing decisions also depend on uncertainty about future employment, income, and wealth, we empirically assess how fertility intentions are affected by job instability, which may severely compromise the employment stability of workers, and economic disadvantages in terms of household income and wealth, which may imply insufficient means to deal with potential adverse future events, thereby generating in the household feelings of anxiety and economic insecurity. We show that the instability of women's work status (i.e., the holding of occasional and precarious jobs) significantly discourages the decision to attempt having a first child. Low levels of household wealth significantly and positively influence the decision to postpone attempting a first child. The chances of further childbirth are significantly and negatively influenced by household income insecurity.
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The Relation between Handedness Indices and Reproductive Success in a Non-Industrial Society
Sara Schaafsma et al.
PLoS ONE, May 2013
Abstract:
The evolution of handedness in human populations has intrigued scientists for decades. However, whether handedness really affects Darwinian fitness is unclear and not yet studied in a non-industrial society where selection pressures on health and handedness are likely to be similar to the situation in which handedness has evolved. We measured both hand preference and asymmetry of hand skill (speed of fine motor control, measured by a pegboard task, and accuracy of throwing), as they measure different aspects of handedness. We investigated the associations between both the direction (left versus right) and strength (the degree to which a certain preference or asymmetry in skill is manifested, independent of the direction) of handedness. We analyzed to what extent these measures predict the number of offspring and self-reported illness in a non-industrial society in Papua, Indonesia. As it is known that body height and fitness are correlated, data on body height was also collected. Due to low numbers of left-handers we could not investigate the associations between direction of hand preference and measures of Darwinian fitness. We found a positive association between strength of asymmetry of hand skill (pegboard) and the number of children men sired. We also found a positive association for men between strength of hand preference and number of children who died within the first three years of life. For women we found no such effects. Our results may indicate that strength of handedness, independent of direction, has fitness implications and that the persistence of the polymorphism in handedness may be ascribed to either balancing selection on strength of asymmetry of hand skill versus strength of hand preference, or sexual antagonistic selection. No relationships between health and handedness were found, perhaps due to disease related selective disappearance of subjects with a specific handedness.
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Kelli Stidham Hall et al.
Journal of Adolescent Health, forthcoming
Purpose: We prospectively examined the influence of young women's depression and psychological stress symptoms on their weekly contraceptive method use.
Methods: We examined data from 689 women ages 18-20 years participating in a longitudinal cohort study. Women completed 8,877 weekly journals over the first year, which assessed reproductive, relationship, and health information. We focused on baseline depression (Center for Epidemiologic Studies-Depression Scale) and stress (Perceived Stress Scale) symptoms and weekly contraceptive method use. Analyses used multivariate random effects and multinomial logistic regression.
Results: Approximately one quarter of women exhibited moderate/severe depression (27%) and stress (25%) symptoms at baseline. Contraception was not used in 10% of weekly journals, whereas coital and noncoital methods were used in 42% and 48% of weeks, respectively. In adjusted models, women with moderate/severe stress symptoms had more than twice the odds of contraception nonuse than women without stress (odds ratio [OR] 2.23, confidence interval [CI] 1.02-4.89, p = .04). Additionally, women with moderate/severe depression (RR .52, CI .40-.68, p < .001) and stress (relative risk [RR] .75, CI .58-.96, p = .02) symptoms had lower relative risks of using long-acting methods than oral contraceptives (OCs; reference category). Women with stress symptoms also had higher relative risks of using condoms (RR 1.17, CI 1.00-1.34, p = .02) and withdrawal (RR 1.29, CI 1.10-1.51, p = .001) than OCs. The relative risk of dual versus single method use was also lower for women with stress symptoms.
Conclusion: Women's psychological symptoms predicted their weekly contraceptive nonuse and use of less effective methods. Further research can determine the influence of dynamic psychological symptoms on contraceptive choices and failures over time.