Why Is Infant Mortality Higher in Boys Than in Girls?

Why Is Infant Mortality Higher in Boys Than in Girls? A New Hypothesis Based on Preconception Environment and Evidence From a Large Sample of Twins

Roland Pongou

Demography
November 2012

Abstract

Infant mortality is higher in boys than girls in most parts of the world. This has been explained by sex differences in genetic and biological makeup, with boys being biologically weaker and more susceptible to diseases and premature death. At the same time, recent studies have found that numerous preconception or prenatal environmental factors affect the probability of a baby being conceived male or female. I propose that these environmental factors also explain sex differences in mortality. I contribute a new methodology of distinguishing between child biology and preconception environment by comparing male-female differences in mortality across opposite-sex twins, same-sex twins, and all twins. Using a large sample of twins from sub-Saharan Africa, I find that both preconception environment and child biology increase the mortality of male infants, but the effect of biology is substantially smaller than the literature suggests. I also estimate the interacting effects of biology with some intrauterine and external environmental factors, including birth order within a twin pair, social status, and climate. I find that a twin is more likely to be male if he is the firstborn, born to an educated mother, or born in certain climatic conditions. Male firstborns are more likely to survive than female firstborns, but only during the neonatal period. Finally, mortality is not affected by the interactions between biology and climate or between biology and social status.

http://link.springer.com/article/10.1007/s13524-012-0161-5

Genetic basis for sex differences in pro-social behaviour

Or to put it another way: women are born to be nicer according to this report of research. Yeah, I know, you told us.

Tolerance

People's attitudes towards others, particularly those who differ in some way, can be quite revealing. Ireland has had a great deal of migration in recent years and the question of our tolerance towards foreign nationals is a topical one.
So whats the evidence? The ESS asked people whether they thought immigrants made the country better or worse. On a scale of 0 to 10 (10 being better) we average about 5.5, hardly a ringing endorsement. Here is the geographical distribution: the Midlands and the West lag behind the rest of the country. People's anwers to the question may depend on whether they perceive their own situation to be threatened by the presence of immigrants for example through competition by foreign workers.
So what about a group who, arguably, pose no threat so that there is no question of a vested interest?Respondents were also asked whether they thought homosexuals should be free to live their life as they wish. About 80% agreed with the statement but there are some interesting regional differences with the West and South-West lagging behind.

Men,women,earnings

The difference in earnings between men and women is one of the most widely commented on statistics about the labour market. It currently features in notices on the back of some Dublin buses. Fame at last. It is also one of the most widely studied by economists. The public and many commentators tend to focus on the unadjusted difference i.e. not controlling for anything.
Economists, of course, want to control for stuff, hours at least as well as education, experience and so on. There are various techniques for looking at this including the well known Blinder-Oaxaca decomposition. "Controlling" for things assumes they are exogenous and if they are not only offers only a partial explanation at best. For example say the "wage gap conditional on educational" is less than the raw, unadjusted gap: so what? As it happens, females do consistently do better than males educationally so conditioning on that will widen the gap, if anything.
Anyway here is the latest news from the Irish labour market on the male-female earnings difference.

Is There Anything Good About Men?

People probably differ sharply about the answer to this question but for a scholarly treatment this book by Roy Baumeister looks fascinating.

Is There Anything Good About Men?: How Cultures Flourish by exploiting men
In Is There Anything Good About Men?, Roy Baumeister offers provocative answers to these and many other questions about the current state of manhood in America. Baumeister argues that relations between men and women are now and have always been more cooperative than antagonistic, that men and women are different in basic ways, and that successful cultures capitalize on these differences to outperform rival cultures. Amongst our ancestors---as with many other species--only the alpha males were able to reproduce, leading them to take more risks and to exhibit more aggressive and protective behaviors than women, whose evolutionary strategies required a different set of behaviors. Whereas women favor and excel at one-to-one intimate relationships, men compete with one another and build larger organizations and social networks from which culture grows. But cultures in turn exploit men by insisting that their role is to achieve and produce, to provide for others, and if necessary to sacrifice themselves. Baumeister shows that while men have greatly benefited from the culture they have created, they have also suffered because of it. Men may dominate the upper echelons of business and politics, but far more men than women die in work-related accidents, are incarcerated, or are killed in battle--facts nearly always left out of current gender debates.

Coffee anyone?

If a meeting becomes stressful, does it help, or make things worse, if team members drink lots of coffee? A study by Lindsay St. Claire and colleagues that set out to answer this question has uncovered an unexpected sex difference. For two men collaborating or negotiating under stressful circumstances, caffeine consumption was bad news, undermining their performance and confidence. By contrast, for pairs of women, drinking caffeine often had a beneficial effect on these same factors. The researchers can't be sure, but they think the differential effect of caffeine on men and women may have to do with the fact that women tend to respond to stress in a collaborative, mutually protective style (known as 'tend and befriend') whereas men usually exhibit a fight or flight response.

The study involved 64 male and female participants (coffee drinkers at the University of Bristol with an average age of 22) completing various construction puzzles, negotiation and collaborative memory tasks in same-sex pairs. They did this after drinking decaffeinated coffee, which either had or hadn't been spiked covertly with caffeine (the equivalent of about three cups' worth of coffee). Stress was elevated for some of the pairs by telling them they would shortly have to give a public presentation, and by warning them that their participation fee would be performance dependent.

How large were the caffeine effects? The men's memory performance under stressful conditions with caffeine was described by the researchers as 'greatly impaired' whereas caffeine didn't affect women in the same situation. For the construction puzzles, caffeine under high stress conditions led men to take an average of twenty seconds longer (compared with no caffeine) whereas it led women to solve the puzzles 100 seconds faster.

St. Claire, L., Hayward, R., and Rogers, P. (2010). Interactive Effects of Caffeine Consumption and Stressful Circumstances on Components of Stress: Caffeine Makes Men Less, But Women More Effective as Partners Under Stress. Journal of Applied Social Psychology, 40 (12), 3106-3129 http://dx.doi.org/10.1111/j.1559-1816.2010.00693.x

From BPS Research Digest, issue 182

Bang goes the theory: menstruation and absenteeism

This paper casts doubt on the well known paper, recently published in the AEA Applied Economics that attributed much of the absenteeism of female workers to menstruation basically as it followed a 28 day cycle and was absent in older (post-menopausal) women. Its important not to be too persuaded by one's own theory, no matter how clever.

Does menstruation explain gender gaps in worker absenteeism
Jonah Rockoff, Mariesa Herrman
Ichino and Moretti (2009) find that menstruation may contribute to gender gaps in absenteeism and earnings, based on evidence that absences of young female Italian bank employees follow a 28-day cycle. We analyze absenteeism of teachers and find no evidence of increased female absenteeism on a 28-day cycle. We also show that the evidence of 28-day cycles in the Italian data is not robust to the correction of coding errors or small changes in specification. We show that five day workweeks can cause misleading group differences in absence hazards at multiples of 7, including 28 days.
NBER 16523

Some Irish boys are better at maths than girls

Differences between the sexes in educational attainment are of interest to many people. In Ireland, as elsewhere, males are being left behind by females in key exams and university entrance. So where does it all start and is it the same for everyone?
Using the Growing up in Ireland data I look at differences in maths score: I estimate quantile regressions controlling for a bunch of chararacteristics (SES, birthweight, maternal smoking, income and more). These show the effect of being male on the maths score at different points of the conditional distribution : so high quantiles are not "high test scores" but "high test scores conditional on the covariates one has included". I interpret this as proxying unobserved ability, this could be cognitive ability but not necessarily. The outcome is scaled to have a mean of 100 and a std deviation of 15.
The results are striking. Boys do better on average so a linear regression gives a coefficient of about 1.2. By comparison, being right-handed or having been breastfed is worth an extra 1.4 points. But at lower quantiles the effects are smaller and are not statistically significant. At higher quantiles the effect is around 4 points.
So I interpret this as saying that at low levels of unobserved ability it doesn't matter if the child is a boy or girl. But for "smarter" children being a boy is an advantage i.e. being male and being "smart" are complements.

Boys just want to have fun?

RTE today carried the shock news that girls outperform boys in the Leaving Certificate. To be fair the article notes that this is not new and is observed internationally. What I am not aware of is evidence (and no, anecdotes - even from taxi-drivers- do not count) on why this is so.
There is no shortage of theories of course: the feminization of teaching, the feeling of displacement and general uselessness by males due to the evils of feminism etc etc. But this seems an important enough trend to be worth studying and, even, doing something about.

Gender Differences in Risk Behaviour: Does Nurture Matter?

Alison L. Booth, Patrick Nolen
Women and men may differ in their propensity to choose a risky outcome because of innate preferences or because pressure to conform to gender-stereotypes encourages girls and boys to modify their innate preferences. Single-sex environments are likely to modify students' risk-taking preferences in economically important ways. To test this, we designed a controlled experiment in which subjects were given an opportunity to choose a risky outcome - a real-stakes gamble with a higher expected monetary value than the alternative outcome with a certain payoff - and in which the sensitivity of observed risk choices to environmental factors could be explored. The results of our real-stakes gamble show that gender differences in preferences for risk-taking are indeed sensitive to whether the girl attends a single-sex or coed school. Girls from single-sex schools are as likely to choose the real-stakes gamble as boys from either co ed or single sex schools

http://d.repec.org/n?u=RePEc:esx:essedp:672&r=cbe

Male/female wage gap

The paper below made me think about the wage gap between males & females (sorry I hate the use of the word "gender" there) & to wonder does behavioural/neuro econ' have anything to say about it.In the asymmetric version of Nash co-operative bargaining, power can be thought of as coming from discount rates: higher discount rates means lower bargaining power.I wonder is this a plausible explanation of sex based differences in bargaining? I'm also curious to know what parts of the brain show activation during the bargaining process for example reward circuits.Maybe some people like the process and hence "hang tough".

Are Women Asking for Low Wages? Gender Differences in Wage Bargaining Strategies and Ensuing Bargaining Success.Säve-Söderbergh, Jenny (Swedish Institute for Social Research, Stockholm University). http://d.repec.org/n?u=RePEc:hhs:sofiwp:2007_007&r=cbe
Men and women’s labor market outcomes differ along pay, promotion and competitiveness. This paper contributes by uncovering results in a related unexplored field using unique data on individual wage bargaining. We find striking gender differences. Women, like men, also bargain, but they submit lower wage bids and are offered lower wages than men. The adjusted gender wage gap is lower with posted-wage jobs than with individual bargaining, although less is ascribable to the term associated with discrimination. Both women and men use self-promoting, or competitive bargaining strategies, but women self-promote at lower levels. Employers reward self-promotion but the larger the self-promotion, the larger is the gender gap in bargaining success. Women therefore lack the incentives to self-promote, which helps to explain the gender disparities.