Skewed sex ratios - operational (OSR) and Adult (ASR) - arise from sexual differences in reproductive behaviours and adult survival rates due to the cost of reproduction. However, skewed sex-ratio at birth, sex-biased dispersal and immigration, and sexual differences in juvenile mortality may also contribute. We present a framework to decompose the roles of demographic traits on sex ratios usin...

Evolutionary theory predicts adaptive adjustment in offspring sex ratio by females. Seasonal change in sex ratio is one possibility, tested here in two sister species, the Common sandpiper and the Spotted sandpiper Actitis hypoleucos and A. macularia. In the monogamous Common sandpiper, males are the most competitive sex. In each of 3 years, there was a change from mainly sons in early clutches...

Research on the neurobiological and behavioral effects of oxytocin (OT), as well as on its possible therapeutic applications, has intensified in the past decade. Accurate determination of peripheral OT levels is essential to reach meaningful conclusions and to motivate, support and inform clinical interventions. Different, but concordant, methods for measuring plasma OT have been developed over...

A content analysis of 191 motion pictures featuring 211 nurses as significant characters was conducted to determine the nature and extent of the motion picture industry's depiction of the nurse as a sex object and to identify changes in that portrayal from 1930 to 1980. Seventy-three percent of the nurse roles characterized nurses as sex objects. The frequency and intensity of stereotypes of nu...

When males provide females with resources at mating, they can become the limiting sex in reproduction, in extreme cases leading to the reversal of typical courtship roles. The evolution of male provisioning is thought to be driven by male reproductive competition and selection for female fecundity enhancement. We used experimental evolution under male- or female-biased sex ratios and limited or...

OBJECTIVE To assess whether perceived role conflict is associated with stimulated pro-inflammatory cytokine production and glucocorticoid sensitivity, and whether these associations are moderated by sex. METHODS 153 healthy adults (aged 45.8±5.5years, 78% female) listed their 3 main social roles and indicated the amount of role conflict they perceived between each pair of social roles. Subseq...

Testis determination in mammals is initiated by expression of SRY in somatic cells of the embryonic gonad. Genetic analyses in the mouse have revealed a requirement for mitogen-activated protein kinase (MAPK) signaling in testis determination: targeted loss of the kinases MAP3K4 and p38 MAPK causes complete XY embryonic gonadal sex reversal. These kinases occupy positions at the top and bottom ...

The gender roles of men and women are continuously changing in heterosexual relationships alongside the ever-increasing flexibility variation preferences, choice, agency, individual needs. This paper delves into role tradition plays between intimate regarding marriage proposals surname changes, as well which sex initiates more when it comes to physical intimacy, emotional long-term commitment.