نتایج جستجو برای: sexual diversity
تعداد نتایج: 302358 فیلتر نتایج به سال:
Engaging key populations, including gender and sexual minorities, is essential to meeting global targets for reducing new HIV infections and improving the HIV continuum of care. Negative attitudes toward gender and sexual minorities serve as a barrier to political will and effective programming for HIV health services. The President's Emergency Plan for AIDS Relief (PEPFAR), established in 2003...
Sexually transmissible diseases (STDs), the most common notifiable infectious conditions, remain major threats to reproductive and public health worldwide. Travelers are particularly vulnerable to STDs, because of voluntary or involuntary sexual behavior while abroad, and are significant vectors who introduce new pathogens and resistant strains to unaffected parts of the world. This article out...
The vast majority of eukaryotic organisms reproduce sexually, yet the nature of the sexual system and the mechanism of sex determination often vary remarkably, even among closely related species. Some species of animals and plants change sex across their lifespan, some contain hermaphrodites as well as males and females, some determine sex with highly differentiated chromosomes, while others de...
This article describes male adolescents' affective history and reasons for initiating or postponing sexual activity, using interviews with 184 males ages 15 to 19 and residing in the city of São Paulo, Brazil, in 2002. Factors for sexual debut included physical attraction, curiosity, and the desire to lose their virginity, suggesting a profile similar to the male social role. Most of the virgin...
An enduring hypothesis for the proximal benefits of sex is that recombination increases the genetic variation among offspring and that this genetic variation increases offspring performance. A corollary of this hypothesis is that mothers that mate multiply increase genetic variation within a clutch and gain benefits due to genetic diversity alone. Many studies have demonstrated that multiple ma...
The need for reproductive assurance during dispersal, along with the pressure of local mate competition, means that the importance of frequent or repeated colonization is implicit in the literature on sexual system evolution. However, there have been few empirical tests of the association between colonization history and sexual system in plants, and none within a single species. Here we use pat...
■ Abstract The extent and diversity of sexual dichromatism in birds is thought to be due to the intensity of current sexual selection on the plumage ornamentation of males and females. This view leads to an expectation of concordance between ecological conditions and sexual dichromatism. Yet, because expression of dichromatism is the result of not only current selection, but also historical pat...
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