BACKGROUND Previous studies estimating the fraction of transmissions from persons with primary HIV have not focused on the effects of switching sex role in male homosexual populations. Such behavioral fluctuations can increase the contribution of primary HIV in the overall population. METHODS We modeled HIV transmission with 8 compartments defined by 4 behavioral groups, with different anal-i...

Classic sex role theory predicts that sexual selection should be stronger in males in taxa showing conventional sex roles and stronger in females in role reversed mating systems. To test this very central prediction and to assess the utility of different measures of sexual selection, we estimated sexual selection in both sexes in four seed beetle species with divergent sex roles using a novel e...

OBJECTIVE The purpose of this integrative literature review was to explore factors that are related to sexual practices among Latino adolescents and identify which of those factors are common across successful sexually transmitted infection (STI)/HIV intervention programs for Latino adolescents. DESIGN An integrative literature review was conducted. Search terms included Latino, Hispanic, edu...

In Caenorhabditis elegans the two sexes, hermaphrodites and males, are thought to be irreversibly determined at fertilization by the ratio of X chromosomes to sets of autosomes: XX embryos develop as hermaphrodites and XO embryos as males. We show instead that both sex and genotype of C. elegans can be altered postembryonically and that this flexibility requires sexual reproduction. When grown ...

BACKGROUND The sexually dimorphic prevalence of autoimmune disease remains one of the most intriguing clinical observations among this group of disorders. While sex hormones have long been recognized for their roles in reproductive functions, within the past 2 decades scientists have found that sex hormones are integral signaling modulators of the mammalian immune system. Sex hormones have defi...

Sexual selection theory predicts a positive correlation between relative parental investment and mate choice. In syngnathid fishes (seahorses and pipefish), males brood offspring in specialized brooding structures. While female-female mating competition has been demonstrated in some pipefishes, all seahorses (genus Hippocampus) studied to date have been found to have conventional sex roles with...

In a number of insects, fishes and birds, the conventional sex roles are reversed: males are the main care provider, whereas females focus on matings. The reversal of typical sex roles is an evolutionary puzzle, because it challenges the foundations of sex roles, sexual selection and parental investment theory. Recent theoretical models predict that biased parental care may be a response to bia...

In this paper we critically review how research on girls or women and sport has developed over the last 35 years. We use a post-positivist lens to explore the content of the papers published in Sex Roles in the area of women, gender and sport and examine the shifts in how gender and sport have been conceptualized in these accounts. In order to initiate a broader dialogue about the scholarly ana...

In modern Western societies women have higher rates of mental illness than men. In this article it is suggested that this difference can be attributed to the role of married women. More specifically, it is shown that married women have noticeably higher rates of mental illness than married men. In contrast, it is shown that when single women are compared with single men, divorced women with div...