BACKGROUND Several family structure-related factors, such as birth order, family size, parental age, and age differences to siblings, have been suggested as risk factors for schizophrenia. We examined how family-structure-related variables modified the risk of schizophrenia in Finnish families with at least one child with schizophrenia born from 1950 to 1976. METHODS We used case-sibling desi...

[This version: January 16, 2015] Abstract We consider two econometric problems when investigating the impact of family size on labor market outcomes using the popular twin-birth instrument. The first is the potential for omitted variable bias caused by the fact that fertility treatments are linked to twin births and are typically unobserved. We present estimates corrected for this bias and find...

The share of household resources devoted to children is hard to identify, because consumption is measured at the household level, and goods can be shared. Using semiparametric restrictions on individual preferences within a collective model, we identify how total household resources are divided up among household members, by observing how each family member’s expenditures on a single private go...

Reproductive behavior cannot be understood without taking the local level of competition into account. Experimental work in great tits (Parus major) showed that (1) a survival cost of reproduction was paid in environments with high levels of competition during the winter period and (2) experimentally manipulated family size negatively affected the ability of parents to compete for preferred bre...

Focusing on the socio-geographical factors that influence local vulnerability to dengue at the village level, spatial regression methods were applied to analyse, over a 5-year period, the village-specific, cumulative incidence of all reported dengue cases among 437 villages in Prachuap Khiri Khan, a semi-urban province of Thailand. The K-order nearest neighbour method was used to define the ran...

Latterly much attention has been attracted, and rightly so, to the number, variety, and potency of the socio-economic factors which strongly incline married couples deliberately to restrain their fertility and thereby to limit the size of-their families. A tendency to overlook a number of purely biological factors which work in the same direction is to be discerned. These latter are for the mos...

The very low fertility experienced in several European countries in recent decades in the presence of higher intended family sizes has renewed interest in fertility intentions data. While the overall level of childbearing in Britain over the past few decades has remained relatively stable and high in comparison with many other European countries, we have seen sizeable increases in the age at wh...

Genomic determinants underlying increased encephalization across mammalian lineages are unknown. Whole genome comparisons have revealed large and frequent changes in the size of gene families, and it has been proposed that these variations could play a major role in shaping morphological and physiological differences among species. Using a genome-wide comparative approach, we examined changes i...

This case study examines the link between marine resource management, and the universal contraceptive use among married couples in the lobster- fishing village of Punta Allen, located in the Sian Ka'an Biosphere Reserve, Quintana Roo, Mexico. Several reasons appear to contribute to small desired and actual family sizes. Some of these include a medical clinic staff effective in promoting family ...

It is important to understand the forces that shape the size and evolutionary histories of gene families. Here, we investigated the evolution of non-protein-coding RNA genes in the genomes of Caenorhabditis nematodes. We specifically focused on nested arrangements, that is, cases in which an RNA gene is entirely contained in an intron of another gene. Comparing these arrangements between specie...