Reproductive
Requiem for Heterosis as a Cause of the Flynn Effect: Positive Combined Effects of Numbers and Lengths of Homozygosity Runs on Offspring-Parent Differences in Educational Attainment
Michael Woodley of Menie et al.
Evolutionary Psychological Science, September 2024, Pages 189–200
Abstract:
It has been argued that reduced inbreeding depression and associated increased heterosis (hybrid vigor), due to greater gene flow between human subpopulations, is the cause of the Flynn effect (rising IQ-test performance over time). Using genotypic data from the Wisconsin Longitudinal Study, three estimates of genome-wide runs of homozygosity (ROH) are generated for a subsample of unrelated individuals of European descent. These estimates are used in a between-generation regression model to predict offspring advantage over parents in educational attainment (EA; years of schooling). After controlling for a variety of covariates, it is found that a variable combining both the numbers and lengths of ROH is a statistically significant positive predictor of the offspring EA advantage. Maternal, rather than paternal, differences are found to drive the effect when these parental influences are examined separately. Since the heterosis hypothesis (HH) explicitly predicts that this analysis would yield the opposite finding, the result constitutes substantial evidence against the HH. By contrast, the life history model of the Flynn effect (LHM) satisfactorily explains the current findings, positing that slowing life history speed increases maternal investment (MI) into offspring exhibiting greater coefficients of genetic relatedness as a means of raising inclusive fitness. According to the LHM, the Flynn effect stems, at least in part, from MI enhancing opportunities for the cultivation of narrow cognitive abilities (e.g., through greater exposure to highly predictable environments, such as in good schools). The significant independent effect of assortative mating observed here is also consistent with the LHM, as are other patterns found in these data.
In search of the genetic variants of human sex ratio at birth: Was Fisher wrong about sex ratio evolution?
Siliang Song & Jianzhi Zhang
Proceedings of the Royal Society: Biological Sciences, October 2024
Abstract:
The human sex ratio (fraction of males) at birth is close to 0.5 at the population level, an observation commonly explained by Fisher’s principle. However, past human studies yielded conflicting results regarding the existence of sex ratio-influencing mutations -- a prerequisite to Fisher’s principle, raising the question of whether the nearly even population sex ratio is instead dictated by the random X/Y chromosome segregation in male meiosis. Here we show that, because a person’s offspring sex ratio (OSR) has an enormous measurement error, a gigantic sample is required to detect OSR-influencing genetic variants. Conducting a UK Biobank-based genome-wide association study that is more powerful than previous studies, we detect an OSR-associated genetic variant, which awaits verification in independent samples. Given the abysmal precision in measuring OSR, it is unsurprising that the estimated heritability of OSR is effectively zero. We further show that OSR’s estimated heritability would remain virtually zero even if OSR is as genetically variable as the highly heritable human standing height. These analyses, along with simulations of human sex ratio evolution under selection, demonstrate the compatibility of the observed genetic architecture of human OSR with Fisher’s principle and render it plausible that multiple OSR-influencing genetic variants segregate among humans.
Involuntary childlessness in the U.S. and Israel: Pronatalism, gender, and sexual identity
Doyle Tate & Geva Shenkman
Journal of Marriage and Family, forthcoming
Method: Two online surveys were distributed, one per country. The combined dataset was 1739 people (470 heterosexual men, 521 heterosexual women, 421 sexual minority men, and 327 sexual minority women). Differences in pronatalism, experiences of involuntary childlessness, and stress related to involuntary childlessness were assessed as a function of gender, sexual identity, and country.
Results: Participants in the U.S. reported higher levels of pronatalism, more frequent involuntary childlessness, and greater stress from these experiences than did Israeli participants. In Israel, 68% of sexual minority people reported having experienced involuntary childlessness compared to 32% of heterosexual people. In the U.S., around 50% of people reported involuntary childlessness regardless of group. However, sexual minority individuals reported more frequent experiences of and stress from these experiences than did heterosexual people in both countries.
NIMBY Syndrome and Abortion Access
David Doherty, Dana Garbarski & Sasha Shapsis
American Politics Research, forthcoming
Abstract:
The potential for “not-in-my-backyard” (NIMBY) sentiments to shape public attitudes is well-documented. However, to date, research on NIMBYism has focused on attitudes about building substantial infrastructure that may undermine property values (e.g., wind turbines; affordable housing) and the opening of facilities like homeless shelters or drug rehabilitation centers that residents may fear will attract unsavory clientele to their neighborhood. Here we demonstrate that NIMBY considerations can also shape attitudes about a “hot button” social issue that is typically not thought of in NIMBY terms: abortion policy. We show that residents of an urban area adjacent to states that recently imposed restrictive abortion policies are less supportive of facilitating abortion access for out-of-state patients when those services would be provided in their own neighborhood, as opposed to in their state.
“Trust Women”: Characteristics of and learnings from patients of a Shield Law medication abortion practice in the United States
Angel Foster et al.
Perspectives on Sexual and Reproductive Health, forthcoming
Introduction: The 2022 Massachusetts Shield Law protects telemedicine providers who care for abortion seekers in other states from criminal, civil, and licensure penalties. In this article we explore the characteristics of patients of The Massachusetts Medication Abortion Access Project (The MAP).
Methods: The MAP is an asynchronous telemedicine service that offers mifepristone/misoprostol to abortion seekers in all 50 states who are at or under 11 weeks pregnancy gestation on initial intake. The MAP charges USD250 using a pay-what-you-can model. We analyzed medical questionnaires and payments submitted by patients who received care from The MAP during its first 6 months of operations using descriptive statistics and for content and themes.
Results: From October 1, 2023–March 31, 2024, 1994 patients accessed care through The MAP. Almost all (n = 1973, 99%) identified as women/girls and about half (n = 984, 49%) were aged 20–29. The MAP cared for patients in 45 states; 84% (n = 1672) of these patients received pills in abortion ban or restricted southern states. Patients paid USD134.50 on average; 29% (n = 577) paid USD25 or less. Nearly two-thirds (n = 1293, 65%) received subsidized care; financial hardship featured prominently in patient comments.