Single women, voluntary childlessness and perceptions about life and marriage

42 single women who want to be childless, 18 who desire a 1 child family, and 42 who want 2 children responded to questions about the quality of their present lives and nature of future marriages. The groups of Australian women were closely matched for age and education, and on current quality of life there were few differences. They had similar levels of positive and negative affect, and described life as enjoyable, interesting, and contented. Those wanting to be childless, however, had rated life as less optimistic and less loving, and also as currently somewhat less satisfying, but life satisfaction was still quite high. These early deciders of childlessness, and those wanting only 1 child, wanted to be financially and socially more independent in future marriage type relationships than women wanting at least 2 children. They also expected to follow interests and careers to their fullest, wanted more role innovative partners, and were somewhat less concerned about home ownership, living to a budget, and keeping contact with family and friends. All women placed considerable importance on the need for trust, self-disclosure, and open communication in a relationship, although the voluntary childless rated more highly the need for intellectual stimulation and for each partner to be happy about the success of their mate. Compared to women wanting 2 children, those wanting to be childless expected a partner to perform a wide range of non-traditional roles in the home.     

Correlates of egg size variation in a population of house sparrow Passer domesticus

Propagule size represents an important life-history trait under maternal control. Despite a positive relationship between propagule size and components of fitness, propagule size displays tremendous amounts of variation which causes are poorly understood within natural populations. With a study of a house sparrows Passer domesticus, we investigate maternal and environmental correlates of egg size, quantify variation in egg size within and between females and broods, and estimate heritability. Egg size had a curvilinear relationship with clutch size and decreased significantly in subsequent broods within seasons. Furthermore, egg size increased with maternal body mass, was positively affected by spring temperatures and curvilinearly related to temperature during the 2 weeks prior to egg laying. Some 46.4 % of variation in egg size was due to differences between females, and 21.9 % was explained by variation between broods by the same female. The heritability of egg size was low (h ² = 0.26) compared to estimates from other studies (h ² > 0.6). The present study challenges the recent idea that egg size is an inflexible maternal characteristic with very high additive genetic variance, and suggests that females are subject to both intrinsic and extrinsic constraints prior to and during egg formation, leading to the observed plasticity in egg size. In a general sense, propagule size could be expected to be both limited by and adaptively adjusted in accordance to prevailing environmental conditions.     

Involuntary childlessness: a neglected problem in poor-resource areas

¹ Correspondence address. Nieuwe Prinsengracht 130, Gebouw G, 1018 VZ Amsterdam, The Netherlands. E-mail: f.vanbalen{at}uva.nl/vabalen{at}hotmail.com Childlessness is analysed on the individual, the national andthe international level. On the individual level five categoriesof consequences are described: grief and sadness; social isolationand stigma; restricted rights; religious effects and economicaspects. The first category concerns individual feelings andthe others are socio-cultural effects in broad-sense. In developingcountries childlessness has consequences on individual and socio-culturallevel. In the West consequences are mostly restricted to individualfeelings. In poor-resource areas there are limited possibilitiesfor modern biomedical treatment. Traditional medicine, withits easy access and cultural acceptation, is a serious ‘competitor’.On the national level there are few incentives and possibilitiesfor development of adequate infertility treatment. Though localand national authorities might be sensitive to the problem,allocation of funds is mostly determined by international agencies,which consider other issues more important. On the internationallevel Western perceptions about the urgency of health issuesare still dominant. In the Western world there is little interestand understanding in the problem of ‘barrenness amongplenty’ because a focus on population growth reductionand on other problems. Also, the perception of childlessnessas an individual problem, makes it difficult to change thisattitude. Possibilities for change are discussed.     

Relationship of income and childlessness

ABSTRACT

We investigated the impact of diabetes on US life expectancy by sex and race/ethnicity using a prospective cohort study design. Cohorts were drawn from 1997 to 2009 waves of the National Health Interview Survey and linked to death records through December 31, 2011. We combined data on the prevalence of diabetes among decedents with estimates of the hazard ratios of individuals diagnosed with diabetes to calculate population attributable fractions (PAFs) by age, sex, and race/ethnicity at ages 30 and above. These estimates were then applied to deaths in the official US life table for 2010 to estimate effects of diabetes on life expectancy.

Diabetes was responsible for a reduction of 0.83 years of life expectancy for men at age 30 and 0.89 years for 30-year-old women. The impact was greatest among Black women at 1.05 years. Estimates based on traditional demographic and actuarial methods using the frequency with which a disease appears as an underlying cause of death on death certificates produced a reduction in life expectancy at age 30 of only 0.33 years.

We conclude that diabetes is substantially reducing US longevity and that its effect is seriously underestimated when using data on underlying causes of death.     

Correlates of dispersal extent predict the degree of population genetic structuring in bats

Dispersal is essential for maintaining demographic and genetic connectivity. For bats, correlates of dispersal extent such as morphology and movement dynamics are reported as having an influence on population genetic structure although these traits exhibit co-variance which has not been previously examined. We used a principal components framework with phylogenetically independent contrasts to compare five dispersal extent predictors (wing loading, aspect ratio, geographic range size, migratory status and median latitude) with population genetic structure among bats. We found that high wing loading values and migration negatively correlate with genetic structure after accounting for co-variance. These findings suggest that bats that can achieve higher flight speeds and migrate seasonally have higher gene flow and resultant genetic connectivity relative to bats that fly slower and do not migrate. These results represent a step towards understanding factors that shaped the genetic structure of bat populations.     

Family background, schooling and childlessness in Australia

Using data from Wave 1 of the Household Income and Labour Dynamics in Australia (HILDA) survey, this paper analyses the extent to which childlessness among Australian women aged 40-54 years varies according to the size and type of family in which they were brought up, and the level and type of schooling they had. Multilevel logistic analysis shows that having been educated in a non-government school, having stayed at school to year 12, having a small number of siblings, at age 14 having a father who was either dead or absent, at age 14 having a father who was employed in a professional occupation, or being a migrant from North or West Europe, North America, East Asia or South-East Asia, all are significantly associated with higher rates of childlessness among women in the 40-54 years age range. The effects of these early lifecourse variables on marital and socioeconomic status in later life, and hence on childlessness, are also considered. The implications of the findings for fertility trends and for Australia's public debate are discussed.     

Development and childlessness in the states and territories of Brazil

Abstract

This article provides an analytical account of the variability in and correlates of Brazil's childlessness rates. Following from the socioeconomic development model, which suggests that involuntary childlessness predominates among developing countries and voluntary childlessness among developed countries, this paper examines the extent to which levels of development are related to age‐specific rates of childlessness in the states and territories of Brazil. We find both variation within the age‐specific childlessness rates and important associations between measures of economic development in 1970 and the rates of childlessness in 1980. Moreover, childlessness in Brazil tends to be more voluntary than involuntary, particularly among the younger women in the more modernized subregions of the country.     

Divorce in Ethiopia: the impact of early marriage and childlessness

Forty-five per cent of first marriages in Ethiopia end in divorce within 30 years, and two-thirds of women who divorce do so within the first 5 years of marriage. This paper looks at two factors that may have an impact on the risk of divorce in Ethiopia: early age of first marriage, and childlessness within the first marriage. Data used were from the 1990 National Family and Fertility Survey conducted by the Government of Ethiopia. A total of 8757 women of reproductive age (15-49) were analysed. Life table analysis was used to determine the median age at first marriage, first birth and the median duration of marriage. Cox models were analysed to determine the differentials of divorce. The results of this analysis showed that both early age at marriage and childlessness have a significant impact on the risk of divorce. An inverse relationship was found between age at marriage and risk of divorce. Having a child within the first marriage also significantly reduced the risk of divorce. In addition, several cultural and socioeconomic variables were significant predictors of divorce.     

Correlates of reproductive success in a Caribbean village

Genealogical, demographic, and economic data collected in a rural Trinidadian village indicate that: (1) individuals with more land have more offspring, (2) males with more land have higher mating success, (3) young adults with parents resident in the village have higher reproductive success, and (4) the residence of father has a strong effect on young adult male reproductive success, but apparently has no effect on young adult female reproductive success, suggesting a gender bias in nepotism. The results indicate that there are important gender differences in the effect of resources on reproduction and in patterns of parent-offspring interaction.     

The post-genomic era for a select few

A report of the 4th Colmar Scientific Symposium 'Biology in the Post-genomic Era', Colmar, France, 16-17 October 2003.     

Nutritional Correlates of Koala Persistence in a Low-Density Population

It is widely postulated that nutritional factors drive bottom-up, resource-based patterns in herbivore ecology and distribution. There is, however, much controversy over the roles of different plant constituents and how these influence individual herbivores and herbivore populations. The density of koala (Phascolarctos cinereus) populations varies widely and many attribute population trends to variation in the nutritional quality of the eucalypt leaves of their diet, but there is little evidence to support this hypothesis. We used a nested design that involved sampling of trees at two spatial scales to investigate how leaf chemistry influences free-living koalas from a low-density population in south east New South Wales, Australia. Using koala faecal pellets as a proxy for koala visitation to trees, we found an interaction between toxins and nutrients in leaves at a small spatial scale, whereby koalas preferred trees with leaves of higher concentrations of available nitrogen but lower concentrations of sideroxylonals (secondary metabolites found exclusively in eucalypts) compared to neighbouring trees of the same species. We argue that taxonomic and phenotypic diversity is likely to be important when foraging in habitats of low nutritional quality in providing diet choice to tradeoff nutrients and toxins and minimise movement costs. Our findings suggest that immediate nutritional concerns are an important priority of folivores in low-quality habitats and imply that nutritional limitations play an important role in constraining folivore populations. We show that, with a careful experimental design, it is possible to make inferences about populations of herbivores that exist at extremely low densities and thus achieve a better understanding about how plant composition influences herbivore ecology and persistence.