What makes a stopping rule sexist?

"Parents' decisions to have children are modeled by a simple stopping rule that describes the probability of having another child as a function of the number of boys and girls already born to the parents. Because the stopping rule depends on the sex of the offspring, the rule may introduce a correlation between sex of offspring and the number of siblings the offspring has. When this is coupled with a correlation between number of siblings and well-being, a correlation between sex and well-being may emerge despite equal treatment of the two sexes within each family. The author provides sufficient conditions on a stopping rule for it to be sexist in the sense that the average well-being of one sex is higher than that of the other sex." (SUMMARY IN FRE)     

A formal theory for male-preferring stopping rules of childbearing: sex differences in birth order and in the number of siblings

Through mathematical deductions, this article shows certain macro-demographic consequences of individually employed male-preferring stopping rules in childbearing. It is shown that male-preferring stopping rules generate differences between boys and girls in birth order and in the number of siblings. Two situations are considered regarding the latent probability of having a boy: population homogeneity and population heterogeneity. The sex difference in the number of siblings exists even under population homogeneity, and the difference remains constant when each couple employs a distinct alternative rule. On the other hand, the sex difference in the birth order exists only under population heterogeneity. Substantive implications of these findings are discussed.     

Family size,schooling and child labor in Peru -- an empirical analysis

This paper analyzes the effects of being indigenous, number of siblings, sibling activities and sibling age structure on child schooling progress and child non-school activity. The analysis is based on the Peru 1991 Living Standards Survey. The analysis shows that family size is important. However, the analysis also demonstrates the importance of taking into consideration the activities of siblings. The number of siblings not entrolled in school proves to be an important control variable in at least one specification of the empirical model. However, more research is needed on the interactions between siblings, their activities and their age structure. In other words, an attempt must be made to find ways of taking into account the “life cycle effects” of one‘s siblings on their schooling performance and labor force activity. The analysis also shows that the age structure of siblings is important, but in conjunction with their activities. That is, having a greater number of younger siblings implies less schooling, more age-grade distortion in the classroom and more child labor. JEL classification: J22, J23, I21 Received August 1, 1996 / Accepted February 21, 1997     

Persistent age distributions for an age‐structured two‐sex population model*

In this paper we formulate an age‐structured two‐sex population model which takes into account a monogamous marriage rule and the duration of marriage. We are mainly concerned with the existence of exponential solutions with a persistent age distribution. First we provide a semigroup method to deal with the time‐evolution problem of our two‐sex population model. Next, by constructing a fixed point mapping, we prove the existence of exponential solutions under homogeneity conditions.     

Age of Onset of Alcohol Consumption and Subsequent Negative Health Outcomes in Gay and Bisexual Men Who Have Sex With Men

ABSTRACT

The correlation between current alcohol use and sexual risk behaviors among men who have sex with men (MSM) is well documented, but little is known about age of drinking onset and current risks among this population. Data from a 2008 Internet survey of 8,452 MSM in the United States were used to assess factors associated with age of onset of alcohol use. In a multivariable model, drinking onset before age 15 was significantly associated with a higher number of lifetime male anal sex partners and being behaviorally bisexual in the past 12 months. Men who reported depressive symptoms in the past two weeks or who screened positive for alcohol abuse in the past 60 days were more likely to have early age of drinking onset. Findings suggest the need for targeting younger adolescents for alcohol screening, particularly sexual minority youth, to prevent risk behaviors in adulthood.     

Determining the impact of sex preferences on fertility: A demonstration study

The stopping rule measure of sex preferences represents a combination of psychological measures of preference and behavioral intentions. This study of 172 college students demonstrates that the stopping rule measure is a useful and practical method of measuring sex preferences. The results further indicate that parity progression ratio measures inherently underestimate the effect of sex preferences on individual fertility because they incorrectly assume that sex preferences (a) are homogeneous within the population and (b) can only act to increase, not to decrease, fertility. Use of the stopping rule measure to predict the possible effects of sex preselection techniques on fertility is also discussed.     

Stopping rule of host search by the parasitoid,Chrysocharis pentheus (Hymenoptera: Eulophidae), in host patches

Summary We studied the stopping rule obeyed by the female parasitoid,Chrysocharis pentheus, in deciding when to leave the leaflet on which she is searching for larvae ofPhytomyza ranunculi. She seemed not to employ some stopping rules that have been suggested; i.e., a fixed-number rule and a fixed-time rule and others. The stopping model formulated forDapsilarthra rufiventris parasitic on the same host species fitted well to the results. The model assumes that the searching female will deposit a marking pheromone on the leaflet at a rate proportional to the search speed and will leave the leaflet when the amount of the pheromone that has accumulated on the leaflet reaches the threshold,L. In this model,L denotes the amount of search effort spent on the leaflet. A comparison of the observed results with the predictions from the model suggested thatL increased markedly at the first encounter with the mine (host), but less at later encounters.C. pentheus appears to employ a mixed strategy of a fixed search-effort and an area-concentrated search. This would confer an adaptive advantage in foraging forP. ranunculi larvae, which are distributed in clumps among leaflets in the field.     

Methods of decomposing the difference between two rates with applications to race‐sex inequality in earnings

Four general methods of decomposing the difference between two rates into several components are provided. For data cross‐classified by several factors, all four methods can be used treating the factors either hierarchically or symmetrically, and within each treatment, the methods are expected to give very similar results. Since the results may differ significantly depending on whether the factors are hierarchical or symmetrical and since there is no objective way of arranging the factors hierarchically, symmetrical treatment of the factors is recommended. The latter approach is used to study race‐sex inequalities in mean annual earnings for year‐round full‐time workers in the United States based on the 1980 census data cross‐classified by education, age, and occupation.     

Family configuration and adolescent sexual attitudes and behavior

Several measures of family configuration, derived from the number, age, and sex of siblings and the number of parents, were related to adolescent sexual attitudes and behavior in a sample of 836 high school-aged teenagers from two Western states. Zero-order correlations showed that sexual intercourseexperience was less common among adolescents who lived with both parents and also among those who had younger siblings. Similarly, the zero-order correlations showed least permissiveattitudes among adolescents who had more siblings, especially younger siblings, and among those who lived with both parents. Controlling for adolescents' age, sex, race, religion, church attendance, and parents' educational attainment, however, essentially eliminated the relationships between family configuration variables and sexual attitudes and behavior. Only parents' marital structure, reflecting whether adolescents lived with both original parents or not, continued to be weakly related to adolescents' sexual attitudes and behvior.     

Milk siblingship,religious and secular: History,applications, and implications for practice

Problem or backgroundMilk kinship has religious and practical importance to Muslim families that is not well understood in Western cultures. The relationship occurs when an infant receives the milk of a woman other than the biological mother, creating familial relationships between the child and the woman whose milk is received. As milk siblings, her children and the recipient infant must never marry each other. Midwives in Western countries may encounter this in relation to human milk banking.AimThis review provides a context for respectfully assisting families with their decision making when they are offered banked milk.MethodsA database search was conducted and other publications were found manually.Review/findingsMilk siblingship can be religious or secular. In Islam similar prohibitions on marriage exist to those for blood relations. The mothers therefore have to be known to each other to prevent an inappropriate marriage. This relationship has been a barrier to use of human milk banks by Muslim families as milk from several mothers is usually pooled. Nevertheless, donor milk has been used for premature neonates in two Islamic countries, applying the religious requirements. Recent interpretations by some Islamic scholars permitting milk banking may be acceptable to some families, but others will heed other rulings.Conclusion/implicationsNICU staff may encounter difficulties in providing banked human milk to infants from Muslim families. Different rulings exist and Muslim families in Western countries come from a variety of traditions. Sensitivity is required to explore these issues with families.     

Kinship and Population Subdivision

The coefficient of kinship between two diploid organisms describes their overall genetic similarity to each other relative to some base population. For example, kinship between parent and offspring of 1/4 describes gene sharing in excess of random sharing in a random mating population. In a subdivided population the statistic F _st describes gene sharing within subdivisions in the same way. Since F _st among human populations on a world scale is reliably 10 to 15%, kinship between two individuals of the same human population is equivalent to kinship between grandparent and grandchild or between half siblings. The widespread assertion that this is small and insignificant should be reexamined.     

Adolescent social isolation and premature mortality in a Swedish birth cohort

Research shows consistently that social ties are important for longevity, and they may be particularly important during adolescence. An absence of social ties, or social isolation, during adolescence may adversely affect long-term health and wellbeing. While prior research has examined associations between isolation from friends and long-term health, and having no siblings and mortality, no study (of which we are aware) considers jointly both the role of having no friends and no siblings, nor more generally with whom adolescents spend time, and the risk of premature mortality. This paper extends the literature by drawing on data from the Stockholm Birth Cohort Study to examine the association between different types of social isolation during adolescence (i.e., an absence of friends, siblings, and time with other adolescents) and the risk of premature mortality by midlife. Results suggest that having no siblings, being unliked at school, and spending (mostly) no time with other adolescents, increases the risk of premature mortality. The association between being unliked and premature mortality was attenuated by demographic and adolescent characteristics. Consistent with our expectations, net of a robust set of covariates, adolescents who had no siblings and mostly spent no time with other adolescents (i.e., isolates) were the group most vulnerable to premature mortality by midlife. However, this was only true for females.

     

The President's Council on Bioethics: Choosing Sex of Children

The ideology of eugenics as it arose in the late nineteenth century was concerned with the perceived negative effects of differential fertility on the “quality” and composition—variously defined—of future generations. Quality was to be raised by preventing or discouraging the “less fit” from propagating themselves and by encouraging childbearing among couples seen as carriers of desirable genetic endowments. Thus, this old‐fashioned eugenics was directed, at least by intent and sometimes in practice, to select among parents and influence their procreative behavior. The rules for such selection were typically decided, democratically or otherwise, on the advice of anointed “experts.” By the mid‐twentieth century these programs had come to be thoroughly discredited, both because they were seen to lack scientific validity and, perhaps especially, as a result of Nazi racial policies. Modern technological developments have given rise to, or created the realistic prospect of, a different, “grassroots” eugenics: parents voluntarily choosing qualities they would prefer their offspring to possess. Their right to do so would seem to be a straightforward extension of the principle, endorsed by numerous international declarations, that “all couples and individuals have the basic right to decide freely and responsibly the number and spacing of their children.” Parents might exercise that right by seeking to improve their children's chances for a healthy and successful life or merely by following their own prejudices. But the application of this principle tacitly assumes that the aggregate outcome of individual reproductive decisions is in reasonable harmony with the collective interest. The technological means now available for parents to select preferred physical and intellectual characteristics of their children—to improve on the outcome of the natural genetic lottery—are rudimentary. Many of them are still in the domain of science fiction. But in one major instance the technology already exists: selecting the sex of children, especially through early determination of the sex of the fetus, which then may be followed by sex‐selective induced abortion. This option has become widely available in recent years. In societies in which there is strong preference for offspring of a particular sex—usually for boys— the result has been a marked deviation from the normal sex ratio at birth. The social implications of such uncoordinated individual choices are perceived as clearly deleterious, hence the practice of sex‐selective abortion is commonly outlawed even when abortion is otherwise permitted. Invoking a social interest that overrides the right of voluntary parental choice of course raises the question whether other untoward effects of socially unregulated fertility might also be grounds for circumscribing parental freedom of choice in childbearing. Socially undesirable patterns of childbearing could be defined as “non‐responsible.” In the United States, the President's Council on Bioethics, appointed in November 2001, is one of the many committees advising the US President on important social issues. The Council consists of 17 members, including noted scientists, physicians, ethicists, social scientists, legal experts, and theologians. It had the mandate, inter alia, to inquire into the human and moral significance of developments in biomedical and behavioral science and technology and to explore specific ethical and policy questions related to these developments. The Council was chaired by Professor Leon R. Kass, a prominent bioethicist from the University of Chicago. Its report, under the title, Beyond Therapy: Biotechnology and the Pursuit of Happiness, was submitted to the President in October 2003. This massive document, which will also be published in book form by a commercial publishing house, is available online at: http://bioethicsprint.bioethics.gov/reports/beyondtherapy . Reproduced below is a section titled Choosing sex of children from Chapter 2 of the report (titled Better Children,). It offers a penetrating analysis and commentary on issues raised by parental selection of children's sex.     

Ecological analysis of adolescent birth rates in Brazil: Association with Human Development Index

BackgroundAdolescent pregnancy is a multidimensional public health problem. It is known that every year in Brazil approximately 1.1 million adolescents become pregnant and around 20% of all newborns are born to teenage mothers.AimThis ecological study describes the spatio-temporal patterns of the percentages of live births to adolescent mothers between the years of 2010 and 2016 in Brazil and their associations with human development indexes in the meso-regions where they reside.MethodsPercentages of live births to adolescent mothers are the ratio between the number of live births to women aged 10–19 years old and total number of live births in each Brazilian meso-regions during the study period. A spatio-temporal Bayesian model was used to associate the percentages of live births to adolescent mothers with the human development index of each meso-region. Moran’s index was used to measure the spatial autocorrelation between the meso-regions at an aggregate level, whereas the local indicator of spatial auto-correlation measured local correlation.FindingsPercentages of live births to adolescent mothers for the whole country were 19.3% in 2010 and 17.5% in 2016. There is a heterogeneous spatial distribution pattern for these percentages, being the highest percentages in the North region (24.8% in 2016) and the lowest percentages in the Southeast region of the country (14.3% in 2016). The Bayesian model showed that meso-regions with lower human development index values have higher percentages of live births to adolescent mothers.ConclusionOur findings suggest that adolescent pregnancy is deeply associated with environmental characteristics.     

The mathematics of sex and marriage,revisited

We analyze the problem of modeling marriages in a two‐sex model of population dynamics. We first deal with the problem of incomplete and inconsistent census data and then use a simulator to compare the performance of a variety of marriage functions in modeling births and couples during the ten‐year period between consecutive U.S. censuses. Unlike most empirical methods for comparing marriage functions based on goodness of fit, the differences in the projections of the various functions in our method are of the same magnitude (or even smaller) than the errors between the projected and real data. We observe that for the population of the United States, the harmonic mean function frequently found and used in the literature is a quite poor performer when compared with many other functions in the family we use.     

A consistency algorithm based on information theory

This paper provides a geometric‐mean solution to the consistency problem of multidimensional demographic projection models, based on the constrained minimization of an entropy function. A comparison with the existing harmonic‐mean solution yields many similarities and almost no differences: both solutions satisfy the properties of availability, monotonicity, homogeneity, competition, and symmetry, and, for both solutions, there is a convenient one‐to‐one relationship between adjustments in aggregate numbers of events, on the one hand, and age‐specific numbers of events, on the other hand. However, one major advantage of the geometric mean is that its corresponding distance function is firmly based on (information) theory.     

Populations with constant immigration

We consider a Leslie‐type model of a one‐sex (female) population of natives with constant immigration. The fertility and mortality schedule of the natives may be below or above replacement level. Immigrants retain their fertility and mortality, their children adopt the fertility and mortality of the natives. It is shown how this model may be written in a homogeneous form (without additive term) with a Leslie‐type matrix. Reproductive values of individuals in each age group are discussed in terms of a left eigenvector of this matrix. The homogeneous form of our projection model permits the transformation into a Markov chain with transient and recurrent states. The Markov chain is the basis for the definition of genealogies, which incorporate immigration. It is shown that genealogies describe the life histories of individuals in a population with immigration. We calculate absorption times of the Markov chain and relate them to genealogies. This extends the theory originally designed for closed populations to populations with immigratioa     

A stochastic version of the malthusian trap model: Consequences for the empirical relationship between economic growth and population growth in LDC's

A stochastic version of the Malthusian trap model relating the growth rate of income per capita to the population growth rate of a given country is described. This model is applied to the a priori evaluation of the cross‐sectional correlation between these two growth rates under two additional assumptions: i) the relations in the model at national levels include country‐specific and time‐invariant random components, and ii) these growth rates are measured with a certain degree of temporal aggregation. It is shown that these two assumptions can explain near‐zero correlations between the two growth rates even if there exist a strongly negative effect of population growth on economic growth. However it is not clear whether these assumptions fully explain such insignificant correlations. Indeed, the implementation of the model is complicated by the structural shifts which are likely to occur in the equations over the course of the demographic transition.     

The Implementation of Preferences for Male Offspring

Over the past quarter century the sex ratio at birth (SRB) has risen above natural levels in a number of countries, mostly in Asia. This rise has been made possible in populations with strong son preference by the increasing availability of safe, effective, and inexpensive technologies to determine the sex of a fetus and to end unwanted pregnancies. This article documents levels and trends in the sex ratio at birth, in preferences for male offspring (using information on desired number of girls and boys), and in the implementation of these preferences. DHS surveys from 61 countries in Africa, Asia, and Latin America and for Indian states are the main source of data. A comparison of desired with actual SRBs finds large gaps in most populations, implying a substantial pent‐up demand for male offspring and the technology to implement this preference. Two types of actions to implement preferences are considered: the practice of contraception to stop childbearing after the desired number of sons has been born and the use of sex‐selective abortion to avoid female births. The second part of the article discusses factors that could influence the SRB, including the promotion of gender equality, and the implications of these factors for future trends.