Fluidez sexual: contextualização histórica e contributos teóricos / Fluidez sexual: contextualización histórico y aportaciones teóricas / Sexual fluidity: historical contextualization and theoretical contributions

RESUMO. Neste estudo, tivemos como objetivo aprofundar o conceito de fluidez sexual pela análise crítica da literatura e de uma síntese integrativa sobre o tema. Nele, analisamos estudos que se debruçam sobre a fluidez sexual, exploramos o conceito, sob orientação do modo como Lisa Diamond o introduz na literatura científica, o define e operacionaliza. Por fim, debruçamo-nos sobre estudos no âmbito da fluidez sexual, a fim de perceber os significados atribuídos, e questionando o potencial viés de gênero que acompanha um conceito situado num tempo e num contexto heteronormativos. Como contributo para o aprofundamento do conceito e reforço das suas potencialidades, são apresentadas reflexões sobre a relação entre a fluidez sexual e a masculinidade hegemônica, uma relação pouco valorizada na literatura científica. Globalmente, este trabalho promove, criticamente e de modo interseccional, o questionamento sobre a fixação no sexo/gênero das pessoas envolvidas numa situação sexual e são discutidas as fronteiras do conceito de fluidez sexual e a sua (im)permeabilidade.

RESUMEN. En este estudio, buscamos profundizar el concepto de fluidez sexual a través de un análisis crítico de la literatura y de una síntesis integradora sobre el tema. Para tal, se analizaron estudios enfocados en la fluidez sexual y se exploró este mismo concepto según la guía de cómo Lisa Diamond lo introduce en la literatura científica, lo define y lo concretiza. El análisis de los estudios en torno de la fluidez sexual se realizó teniendo como objetivos comprender los significados atribuidos al concepto y cuestionar el posible sesgo de género que acompaña un concepto ubicado en un tiempo y en un contexto heteronormativos. De cara a profundizar el concepto y reforzar su potencial, se presentan reflexiones sobre la relación entre la fluidez sexual y la masculinidad hegemónica, una relación que no se tiene en cuenta habitualmente en la literatura científica. En general, este trabajo contribuye, de manera crítica e interseccional, al cuestionamiento sobre la fijación en el sexo/género de las personas involucradas en una situación sexual y discute los límites del concepto de fluidez sexual y su (im)permeabilidad.

ABSTRACT. In this study, we sought to deepen the concept of sexual fluidity through a critical analysis of the literature and an integrative synthesis on the topic. In it, we analyzed studies that focus on sexual fluidity, explored the concept, under the guidance of how Lisa Diamond introduces it into the scientific literature, defines it, and operationalizes it. Finally, we focused on studies on sexual fluidity, trying to understand the meanings attributed to the concept, questioning the potential gender bias that accompanies a concept located in a heteronormative time and context. As a contribution to the deepening of the concept and reinforcement of its potential, reflections are presented on the relationship between sexual fluidity and hegemonic masculinity, a relationship that is little valued in the scientific literature. Overall, this work promotes, critically and in an intersectional way, the questioning about the fixation in sex/gender of people involved in a sexual situation and discussed the boundaries of the concept of sexual fluidity and its (im)permeability.

Male Ejaculatory Endophenotypes: Revealing Internal Inconsistencies of the Concept in Heterosexual Copulating Rats.

Distinct manifestations of sexual behavior are conceived as separate phenotypes. Each sexual phenotype is assumed to be associated with a characteristic brain. These notions have justified the phenotyping of heterosexual copulator males based upon their ejaculation's latencies (EL) or frequencies (i.e., cumulative ejaculation number; EN). For instance, men and male rats showing premature, normal or retarded ejaculation are assumed to be distinctive endophenotypes. This concept, nonetheless, contradicts past and recent evidence that supports that sexual behavior is highly variable within each sex, and that the brain sexual functional morphology represents an intricate sexual phenotypic mosaic. Hence, for ejaculatory male endophenotypes to be considered as a valid biological concept, it must show internal consistency at various levels of organization (including genetic architectures), after being challenged by intrinsic and/or extrinsic factors. We then judged the internal consistency of the presumed ejaculatory endophenotypes by assessing whether copulatory behavior and the expression of copulation relevant genes and brain limbic structures are specific to each of the presumed EL- or EN-ejaculatory endophenotypes. To do this, copulating male rats were first phenotyped in groups consistently displaying short, average or long ejaculation latencies or very high, high, average, low or very low EN, based in their copulatory performance. Then, the internal consistency of the presumed EL- or EN-endophenotypes was tested by introducing as covariates of phenotyping other copulatory parameters (e.g., number of intromissions) in addition to EL or EN, or by analyzing the expression levels of genes encoding for estrogen receptor alpha, progesterone receptor, androgen receptor, aromatase, DNA methyl-transferase 3a and DNA methyl-transferase 1 in the amygdala, medial preoptic area, ventromedial hypothalamus and olfactory bulb. We found that even though there were group-level differences in all the variables that were studied, these differences did not add-up to create the presumed EL- or EN-ejaculatory endophenotypes. In fact, the extensive overlapping of copulatory parameters and expression levels of copulation relevant genes in limbic structures across EL- or EN-phenotyped copulating male rats, is not consistent with the hypothesis that distinct ejaculatory endophenotypes exist and that they are associated with specific brain characteristics.