An Integrative Model of Inter- and Intragenerational Preconception Processes Influencing Birthweight in the United States

Social inequalities in birth weight are an important population health concern as low birth weight is one mechanism through which inequalities are reproduced across generations. Yet we don’t understand what causes adverse birth outcomes. This study draws together theoretic and empiric findings from disparate disciplines—sociology, economics, public health, and behavior genetics—to develop a new integrative intra- and inter-generational model of preconception processes influencing birth weight. This model is empirically tested using structural equation modeling and population-level data containing linked mother-daughter pairs from the National Longitudinal Survey of Youth (NLSY79) and the Children of the NLSY79 (N=1,580 mother-daughter pairs). Results reveal that birth weight is shaped by preconception factors dating back to women’s early life experiences as well as conditions dating back three generations, via integrative intra- and inter-generational processes. These processes reveal specific mechanisms through which social inequality can transmit from mothers to children via birth weight

A Closer Look at the Second Demographic Transition in the US: Evidence of Bidirectionality from a Cohort Perspective (1982–2006)

Second demographic transition (SDT) theory posits that increased individualism and secularization have contributed to low fertility in Europe, but very little work has directly tested the salience of SDT theory to fertility trends in the U.S. Using longitudinal data from a nationally representative cohort of women who were followed throughout their reproductive years (NLSY79), this study examines the role of several key indicators of the second demographic transition (secularization, egalitarianism, religious affiliation, and female participation in the labor market) on fertility behavior over time (1982–2006). Analyses employ Poisson estimation, logistic regression, and cross-lagged structural equation models to observe unidirectional and bidirectional relationships over the reproductive life course. Findings lend support to the relevance of SDT theory in the U.S. but also provide evidence of "American bipolarity" which distinguishes the U.S. from the European case. Furthermore, analyses document the reciprocal nature of these relationships over time which has implications for how we understand these associations at the individual-level

Obesity, school obesity prevalence, and adolescent childbearing among U.S. young women

In the United States, adolescent obesity reduces young women’s odds of forming romantic and sexual partnerships but increases the likelihood of risky sexual behavior when partnerships occur. This led us to conduct a study examining the relationship between adolescent obesity and adolescent childbearing. Our study has two aims. We draw from prior research to develop and test competing hypotheses about the association between adolescent obesity and young women’s risk of an adolescent birth. Drawing from risk regulation theory, we also examine whether the association between obesity and young women’s risk of an adolescent birth may vary across high schools with different proportions of obese adolescents. Multilevel logistic regression models are used to analyze data from 4242 female students in 102 U.S. high schools who participated in Wave I (1994–1995) of the National Longitudinal Study of Adolescent Health. Results are the first to show that obesity reduces female adolescents’ odds of childbearing, but that this association is not uniform across schools with different proportions of obese students. As the obesity prevalence in a school increases, so do obese young women’s odds of childbearing. We conclude that understanding whether and how obesity is associated with young women’s odds of having an adolescent birth requires attention to the weight context of high schools

Wallpaper Fermions and the Nonsymmorphic Dirac Insulator

Recent developments in the relationship between bulk topology and surface crystal symmetry have led to the discovery of materials whose gapless surface states are protected by crystal symmetries. In fact, there exists only a very limited set of possible surface crystal symmetries, captured by the 17 "wallpaper groups." We show that a consideration of symmetry-allowed band degeneracies in the wallpaper groups can be used to understand previous topological crystalline insulators, as well as to predict new examples. In particular, the two wallpaper groups with multiple glide lines, $pgg$ and $p4g$, allow for a new topological insulating phase, whose surface spectrum consists of only a single, fourfold-degenerate, true Dirac fermion. Like the surface state of a conventional topological insulator, the surface Dirac fermion in this "nonsymmorphic Dirac insulator" provides a theoretical exception to a fermion doubling theorem. Unlike the surface state of a conventional topological insulator, it can be gapped into topologically distinct surface regions while keeping time-reversal symmetry, allowing for networks of topological surface quantum spin Hall domain walls. We report the theoretical discovery of new topological crystalline phases in the A$_2$B$_3$ family of materials in SG 127, finding that Sr$_2$Pb$_3$ hosts this new topological surface Dirac fermion. Furthermore, (100)-strained Au$_2$Y$_3$ and Hg$_2$Sr$_3$ host related topological surface hourglass fermions. We also report the presence of this new topological hourglass phase in Ba$_5$In$_2$Sb$_6$ in SG 55. For orthorhombic space groups with two glides, we catalog all possible bulk topological phases by a consideration of the allowed non-abelian Wilson loop connectivities, and we develop topological invariants for these systems. Finally, we show how in a particular limit, these crystalline phases reduce to copies of the SSH model.Comment: Final version, 6 pg main text + 29 pg supplement, 6 + 13 figure

Optimal timing for elective egg freezing

To estimate the optimal age to pursue elective oocyte cryopreservation

How Much In-Kind Support Do Low-Income Nonresident Fathers Provide? A Mixed-Method Analysis

Past child support research has largely focused on cash payments made through the courts (formal support) or given directly to the mother (informal support), almost to the exclusion of a third type: non-cash goods (in-kind support). Drawing on repeated, semistructured interviews with nearly 400 low-income noncustodial fathers, the authors found that in-kind support constitutes about one quarter of total support. Children in receipt of some in-kind support receive, on average, $60 per month worth of goods. Multilevel regression analyses demonstrated that children who are younger and have more hours of visitation, as well as those whose father has a high school education and no current substance abuse problem, receive in-kind support of greater value. Yet children whose fathers lack stable employment, or are Black, receive a greater proportion of their total support in kind. A subsequent qualitative analysis revealed that fathers' logic for providing in-kind support is primarily relational, and not financial

The Educational Consequences of Teen Childbearing

A huge literature shows that teen mothers face a variety of detriments across the life course, including truncated educational attainment. To what extent is this association causal? The estimated effects of teen motherhood on schooling vary widely, ranging from no discernible difference to 2.6 fewer years among teen mothers. The magnitude of educational consequences is therefore uncertain, despite voluminous policy and prevention efforts that rest on the assumption of a negative and presumably causal effect. This study adjudicates between two potential sources of inconsistency in the literature—methodological differences or cohort differences—by using a single, high-quality data source: namely, The National Longitudinal Study of Adolescent Health. We replicate analyses across four different statistical strategies: ordinary least squares regression; propensity score matching; and parametric and semiparametric maximum likelihood estimation. Results demonstrate educational consequences of teen childbearing, with estimated effects between 0.7 and 1.9 fewer years of schooling among teen mothers. We select our preferred estimate (0.7), derived from semiparametric maximum likelihood estimation, on the basis of weighing the strengths and limitations of each approach. Based on the range of estimated effects observed in our study, we speculate that variable statistical methods are the likely source of inconsistency in the past. We conclude by discussing implications for future research and policy, and recommend that future studies employ a similar multimethod approach to evaluate findings

Neighborhood and Family Environment of Expectant Mothers May Influence Prenatal Programming of Adult Cancer Risk: Discussion and an Illustrative DNA Methylation Example

Childhood stressors including physical abuse predict adult cancer risk. Prior research portrays this finding as indirect through coping behaviors including adult smoking or through increased toxic exposures during childhood. Little is known about potential direct causal mechanisms between early-life stressors and adult cancer. Because prenatal conditions can affect gene expression by altering DNA methylation with implications for adult health, we hypothesize that maternal stress may program methylation of cancer-linked genes during gametogenesis