Birth order

Kevin Lewis

October 14, 2017

Is There Still Son Preference in the United States?
Francine Blau et al.
NBER Working Paper, September 2017


In this paper, we use 2008-2013 American Community Survey data to update and further probe Dahl and Moretti’s (2008) son preference results, which found evidence that having a female first child increased the probability of single female headship and raised fertility. In light of the substantial increase in immigration, we examine this question separately for immigrants and natives. Among the population in the aggregate, as well as among the native-born separately, consistent with Dahl and Moretti (2008), we find that having a female first child raises the likelihood that the mother is a single parent. However, in sharp contrast to Dahl and Moretti (2008), we find that having a female first child is actually associated with lower fertility. Thus, by the 2008-2013 period, any apparent son preference among natives in their fertility decisions appears to be outweighed by factors such as cost concerns in raising girls. This change may be plausible in light of the reversal of the gender gap in college attendance beginning in the 1980s (Goldin, Katz and Kuziemko 2006), making girls more costly. For immigrants, we also find evidence that having a female first child contributes to female headship, with an effect that has the same magnitude as that for natives although is not statistically significant. However, in contrast to natives, we do find a positive fertility effect, suggesting son preference in fertility among this group. This interpretation is further supported by evidence that, for both first and second generation immigrants (second generation immigrants were examined using the Current Population Surveys) having a girl has a more positive effect on fertility for those whose source countries have lower values of the World Economic Forum’s Gender Equity Index, or lower female labor force participation rates and higher sex (boy-to-girl) ratios among births. We also examine sex selection and find no evidence that sex selection has spread beyond the race groups identified in previous work (e.g., Almond and Edlund 2008).

Did Parental Involvement Laws Grow Teeth? The Effects of State Restrictions on Minors' Access to Abortion
Caitlin Knowles Myers & Daniel Ladd
Middlebury College Working Paper, August 2017


We compile data on the locations of abortion providers and enforcement of parental involvement laws to document dramatic increases in the distances minors must travel if they wish to obtain an abortion without involving a parent or judge. Between 1992 – the year the U.S. Supreme Court established the undue burden standard in Planned Parenthood v. Casey – and present, the average distance to a confidential abortion has increased from 55 to 454 miles. Using both double and triple-difference estimation strategies, we estimate the effects of parental involvement laws, and allow these effects to vary with the distances minors might travel to avoid them. Our results confirm previous findings that parental involvement laws did not increase teen births in the pre-Casey era, and provide new evidence that in more recent decades they have increased teen birth by an average of 3 percent. The estimated effects are increasing in avoidance distance to the point that a confidential abortion is more than a day's drive away, and also are 4 to 6 times greater in counties with high rates of poverty. We estimate that over the past 25 years, parental involvement laws have resulted in half a million additional teen births.

The Children of the Missed Pill
Tomás Rau, Miguel Sarzosa & Sergio Urzúa
NBER Working Paper, October 2017


We use sharp, massive and unexpected price increases of oral contraceptives—product of a documented case of collusion among pharmaceutical retailers in Chile — as a natural experiment to estimate the impact of access to the Pill on fertility and newborn health. Our empirical strategy combines multiple sources of information and takes into account the seasonality of conceptions and the general trends of fertility, as well as the dynamics that arise after interrupting Pill's intake. Our estimates suggest that due to the price hike, the weekly birth rate increased by 4%. We show large effects on the number of children born to unmarried mothers, from mothers in their early 20's, and to primiparae women. Moreover, we find evidence of significant deterioration of newborn health as measured by the incidence of low birthweight and infant mortality. We suggest that the “extra” conceptions faced dire conditions during gestation as a result of mothers' unhealthy behaviors. In addition, we document a disproportional increase of 27% in the weekly miscarriage and stillbirth rates, which we interpret as manifestations of active efforts of termination in a country where abortion was illegal. As the “extra” children reached school age, we find lower school enrollment rates and higher participation in programs for students with special needs. Our results suggest that access to contraceptives may prevent conceptions that will turn out to be in relatively poor health, and thereby may improve the average health of children conceived.

Neoliberal Beliefs and Perceptions of Unintended Adolescent Pregnancy after Consensual or Forced Sex
Jennifer Katz, Claire Gravelin & Caroline O’Brien
Sex Roles, forthcoming


From a neoliberal perspective, young women are free to make autonomous choices and are personally responsible for the outcomes of these choices. Neoliberal ideals may appear to empower women as free sexual agents; however, an individualistic focus on self-sufficiency and personal responsibility may lead to harsh, decontextualized responses to those who experience unintended outcomes. We hypothesized that observers with stronger neoliberal beliefs would show more stigmatizing responses to an unintentionally pregnant adolescent. We also explored whether these expected associations would be moderated by whether or not the young woman chose to consent to sex. U.S. undergraduate students (n = 200) completed a measure of neoliberal beliefs and were randomly assigned to read one of two scenarios in which an adolescent became pregnant after either consensual or forced sex. As expected, participants with stronger neoliberal beliefs were more blaming toward the adolescent for becoming pregnant, felt less sympathy toward her, and had less positive attitudes about her receiving help. These associations remained after controlling for general political ideology and regardless of whether the pregnancy was due to consensual or forced sex. Our results suggest that, for the neoliberal observer, young women are held personally responsible for even uncontrollable sexual and reproductive outcomes.

Medically Necessary but Forbidden: Reproductive Health Care in Catholic-owned Hospitals
Elaine Hill, David Slusky & Donna Ginther
NBER Working Paper, September 2017


The United States has recently seen a large increase in hospital mergers and acquisitions, and Catholic hospital systems have actively participated in this. As of 2016, 40% of the largest healthcare systems were faith-based, with 141 mergers between Catholic and non-Catholic systems since 1997. Mergers that affiliate a hospital with a Catholic owner, network, or system, are consequential because they reduce the set of possible medical procedures since Catholic hospitals are generally prohibited from providing procedures like tubal ligation. We examine the effect of changes in ownership from secular to Catholic (and vice versa) on reproductive health procedures that are likely to be affected. Using hospital-level variation in ownership status for 1002 hospitals, we estimate a difference-in-differences model with year and hospital fixed effects. We find that Catholic hospitals reduce the per bed annual rates of inpatient abortions by 30% and tubal ligations by 31%, whereas there is no significant change in related procedures such as D&Cs or C-sections. Our results are primarily driven by hospitals that change from not Catholic to Catholic. Across a variety of measures, we find minimal overall welfare reductions. However, this decrease in tubal ligations rate alone represents nearly 10,000 fewer tubal ligations per year across the United States, which in itself imposes a substantial cost on women and their partners.

Older fathers' children have lower evolutionary fitness across four centuries and in four populations
Ruben Arslan et al.
Proceedings of the Royal Society: Biological Sciences, 13 September 2017


Higher paternal age at offspring conception increases de novo genetic mutations. Based on evolutionary genetic theory we predicted older fathers' children, all else equal, would be less likely to survive and reproduce, i.e. have lower fitness. In sibling control studies, we find support for negative paternal age effects on offspring survival and reproductive success across four large populations with an aggregate N > 1.4 million. Three populations were pre-industrial (1670–1850) Western populations and showed negative paternal age effects on infant survival and offspring reproductive success. In twentieth-century Sweden, we found minuscule paternal age effects on survival, but found negative effects on reproductive success. Effects survived tests for key competing explanations, including maternal age and parental loss, but effects varied widely over different plausible model specifications and some competing explanations such as diminishing paternal investment and epigenetic mutations could not be tested. We can use our findings to aid in predicting the effect increasingly older parents in today's society will have on their children's survival and reproductive success. To the extent that we succeeded in isolating a mutation-driven effect of paternal age, our results can be understood to show that de novo mutations reduce offspring fitness across populations and time periods.

A father effect explains sex-ratio bias
Aurelio Malo et al.
Proceedings of the Royal Society: Biological Sciences, 30 August 2017


Sex ratio allocation has important fitness consequences, and theory predicts that parents should adjust offspring sex ratio in cases where the fitness returns of producing male and female offspring vary. The ability of fathers to bias offspring sex ratios has traditionally been dismissed given the expectation of an equal proportion of X- and Y-chromosome-bearing sperm (CBS) in ejaculates due to segregation of sex chromosomes at meiosis. This expectation has been recently refuted. Here we used Peromyscus leucopus to demonstrate that sex ratio is explained by an exclusive effect of the father, and suggest a likely mechanism by which male-driven sex-ratio bias is attained. We identified a male sperm morphological marker that is associated with the mechanism leading to sex ratio bias; differences among males in the sperm nucleus area (a proxy for the sex chromosome that the sperm contains) explain 22% variation in litter sex ratio. We further show the role played by the sperm nucleus area as a mediator in the relationship between individual genetic variation and sex-ratio bias. Fathers with high levels of genetic variation had ejaculates with a higher proportion of sperm with small nuclei area. This, in turn, led to siring a higher proportion of sons (25% increase in sons per 0.1 decrease in the inbreeding coefficient). Our results reveal a plausible mechanism underlying unexplored male-driven sex-ratio biases. We also discuss why this pattern of paternal bias can be adaptive. This research puts to rest the idea that father contribution to sex ratio variation should be disregarded in vertebrates, and will stimulate research on evolutionary constraints to sex ratios — for example, whether fathers and mothers have divergent, coinciding, or neutral sex allocation interests. Finally, these results offer a potential explanation for those intriguing cases in which there are sex ratio biases, such as in humans.

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