Family structure and age at menarche: A children-of-twins approach

Girls who grow up in households with an unrelated adult male reach menarche earlier than peers, a finding hypothesized to be an evolutionary strategy for families under stress. The authors tested the alternative hypothesis that nonrandom selection into stepfathering due to shared environmental and/or genetic predispositions creates a spurious relation between stepfathering and early menarche. Using the unique controls for genetic and shared environmental experiences offered by the children-of-twins design, the authors found that cousins discordant for stepfathering did not differ in age of menarche. Moreover, controlling for mother's age of menarche eliminated differences in menarcheal age associated with stepfathering in unrelated girls. These findings strongly suggest selection, and not causation, accounts for the relationship between stepfathering and early menarche.

Scaffolding and bilingual shared reading experiences: Promoting primary school students' learning and development

This paper explores the connections between scaffolding, second language learning and bilingual shared reading experiences. A socio- cultural theory of cognition underpins the investigation, which involved implementing a language and culture awareness program (LCAP) in a year 4 classroom and in the school community. Selected passages from observations are used to analyse the learning of three students, particularly in relation to languages other than English (LOTE). As these three case study students interacted in the classroom, at home and in the community, they co-constructed, appropriated and applied knowledge form one language to another. Through scaffolding, social spaces were constructed, where students learning and development were extended through a variety of activities that involved active participation, such as experimenting with language, asking questions and making suggestions. Extending these opportunities for student learning and development is considered in relation to creating teaching and learning environments that celebrate socio-cultural and linguistic diversity.

Genetic and Cultural Transmission of Smoking Initiation: An Extended Twin Kinship Model

Background Considerable evidence from twin and adoption studies indicates that genetic and shared environmental factors play a significant role in the initiation of smoking behavior. Although twin and adoption designs are powerful to detect genetic and environmental influences, they do not provide information on the processes of assortative mating and parent–offspring transmission and their contribution to the variability explained by genetic and/or environmental factors. Methods We examined the role of genetic and environmental factors for smoking initiation using an extended kinship design. This design allows the simultaneous testing of additive and non-additive genetic, shared and individual-specific environmental factors, as well as sex differences in the expression of genes and environment in the presence of assortative mating and combined genetic and cultural transmission. A dichotomous lifetime smoking measure was obtained from twins and relatives in the Virginia 30,000 sample. Results Results demonstrate that both genetic and environmental factors play a significant role in the liability to smoking initiation. Major influences on individual differences appeared to be additive genetic and unique environmental effects, with smaller contributions from assortative mating, shared sibling environment, twin environment, cultural transmission and resulting genotype–environment covariance. The finding of negative cultural transmission without dominance led us to investigate more closely two possible mechanisms for the lower parent–offspring correlations compared to the sibling and DZ twin correlations in subsets of the data: (i) age × gene interaction, and (ii) social homogamy. Neither mechanism provided a significantly better explanation of the data, although age regression was significant. Conclusions This study showed significant heritability, partly due to assortment, and significant effects of primarily non-parental shared environment on smoking initiation.

Reflections on the centrality of power in medical sociology: an empirical test and theoretical elaboration

This paper explores the contemporary relevance of sociological theorisations centred on medical power, including the medical dominance and deprofessionalisation theses. To achieve this it examines two issues that have been tentatively linked to the relative decline of the power and autonomy of biomedicine - complementary and alternative medicine (CAM) and the Internet-informed patient. Drawing on these two different but interconnected social phenomena, this paper reflects on the potential limitations of power-based theorisations of the medical profession and its relationship to patients and other non-biomedically situated professional groups. It is argued that power-based conceptual schemas may not adequately reflect the non-linear and complex strategic adaptations that are occurring among professional groups.

Social indicators and comparisons of living standards

Construction of an international index of standards of living, incorporating social indicators and economic output, typically involves scaling and weighting procedures that lack welfare-economic foundations. Revealed preference axioms can be used to make quality-of-life comparisons if we can estimate the representative household's production technology for the social indicators. This method is applied to comparisons of gross domestic product (GDP) and life expectancy for 58 countries. Neither GDP rankings, nor the rankings of the Human Development Index (HDI), are consistent with the partial ordering of revealed preference. A method of constructing a utility-consistent index incorporating both consumption and life expectancy is suggested. (C) 2003 Elsevier Science B.V. All rights reserved.