94 research outputs found
Genetic factors increase fecundity in female maternal relatives of bisexual men as in homosexuals.
No full textABSTRACT
Introduction. Recent studies on male homosexuals showed increased fecundity of maternal female relatives of homosexual probands, compared to those of heterosexual controls. We have suggested that these data could be explained by the transmission, in the maternal line, of an X-linked genetic factor that promotes androphilic behavior in females and homosexuality in males.
Aim. Our original studies were on relatives of male subjects who declared themselves to be exclusively homosexual. However, the relationship between homosexuality and bisexuality, including the possibility of shared genetic factors, is complex and largely unexplored. To cast light on this issue, in the present study we examined whether relatives of bisexuals show the same indirect fitness advantage as previously demonstrated for homosexuals.
Main Outcome Measures. Subjects completed a questionnaire on their sexual orientation, sexual behavior, and their own and their relatives' fecundity.
Methods. We studied 239 male subjects, comprising 88 who were exclusively or almost exclusively heterosexual (pooled to comprise our “heterosexual” group), 86 who were bisexual, and 65 exclusively or almost exclusively homosexual individuals (pooled in our “homosexual” group). Bisexuals were here defined on the basis of self-identification, lifetime sexual behavior, marital status, and fecundity.
Results. We show that fecundity of female relatives of the maternal line does not differ between bisexuals and homosexuals. As in the previous study on homosexuals, mothers of bisexuals show significantly higher fecundity, as do females in the maternal line (cumulated fecundity of mothers, maternal grandparents, and maternal aunts), compared to the corresponding relatives of heterosexual controls.This study also shows that both bisexuals and homosexuals were more frequently second and third born. However, only homosexuals had an excess of older male siblings, compared to heterosexuals.
Conclusions. We present evidence of an X-chromosomal genetic factor that is associated with bisexuality in men and promotes fecundity in female carriers. Camperio Ciani A, Iemmola F, and Blecher SR. Genetic factors increase fecundity in female maternal relatives of bisexual men as in homosexuals. J Sex Med 2009;6:449–455
Implicit Measurements of Sexual Preference in Self-Declared Heterosexual Men: A Pilot Study on the Rate of Androphilia in Italy
No full textAbstract
Introduction
An unambiguous measurement of the rate of nonheterosexuality in the male population (male bisexuality and homosexuality) is essential to estimate the health risks associated with same-sex sexual behavior and to scale social and health programs for these citizens. However, self-reported questionnaires on explicit measures of sexual orientation yield significant underestimations of nonheterosexuality. A necessary prerequisite for nonheterosexual preference is androphilia (sexual–erotic attraction to males), which can be explored through psychological tests.
Aims
This study, using a pilot sample, investigates the possibility to inventory the frequency of male androphilia in the general population through a sexual preference implicit association test (sp-IAT). This test is a classical IAT that is based on an association of pictures and words and is easily portable.
Methods
First we conducted a preliminary validation of the specific IAT protocol on 24 control subjects; then, we examined a sample of 150 adult males in Italy as a pilot study. The subjects responded to the sp-IAT and completed the explicit Kinsey scale questionnaire.
Main Outcome Measures
Kinsey scale scores and D value of sp-IAT for both preliminary and pilot sample.
Results
On the explicit Kinsey scale, 2.7% of the sample declared themselves to be sexually attracted to men, corresponding to previous explicit samplings of the Italian homosexual male population. However, the sp-IAT identified that 11.3% of self-declared gynephilic heterosexuals showed a moderate to strong androphilia with a significant effect size (D) always below −0.2, and another 5.6% of the heterosexual sample showed no preference for females (D between −0.2 and 0).
Conclusion
The Kinsey questionnaire strongly dichotomized the responses as either attracted to females or attracted to men, whereas the sp-IAT showed a wider distribution of responses from gynephilia to androphilia. In conclusion, the sp-IAT could be a novel and unambiguous instrument useful to ascertain androphilia population prevalence as a proxy for possible male nonheterosexuality. Camperio Ciani A and Battaglia U. Implicit measurements of sexual preference in self-declared heterosexual men: A pilot study on the rate of androphilia in Italy. J Sex Med 2014;11:2207-2217
Genetic Influences on Male Homosexuality
No full textSexual orientation, identity and desire is the final product of complex interactions between factors such as genetic influences, epigenetic, developmental pathways, both prenatal such as sex hormones, including the maternal factors acting on the foetus, and postnatal factors including shared environmental influences such as family education, social and cultural influences, and nonshared environmental influence such as unique personal experiences. Male homosexuality poses an evolutionary dilemma as it entails reduced fitness but is nevertheless, in part, influenced by genetic factors. Examining the causes of homosexuality the author investigates the Darwinian dilemma as to why genetic factors that influence homosexual nonreproductive behaviour can be maintained in the population without disappearing as expected. Sexually antagonistic selection can explain male homosexuality. A sexually antagonistic model with genetic factors partially linked to X chromosome by increasing fecundity in females and influencing homosexuality in males could be selectively balanced in the population and explain all the peculiarity of male homosexuality
The human dimension of the recent decline and possible recovery of the central Middle Atlas forest in Morocco.
No full textImportance of the Middle Atlas region
The Middle Atlas mixed forest region is an important and now vulnerable ecosystem. It is the last large forest of a
once widely distributed ecosystem around the Mediterranean, and now confined to few areas in Algeria and
Morocco (Thirgood, 1984). This ecosystem is characterized by the Cedar (Cedrus atlantica) and various species of
Oak (Quercus rotundifolia, Q. faginea etc.). The only other mixed Cedar forest can be found in relict areas of
Lebanon, in the island of Cyprus, and in the south west Anatolia region in Turkey. The Middle Atlas mosaic forest
system is therefore the last remaining large north African forest.
Wildlife
In this forest until quite recent the last population of the Berber Lion and Leopard could be found. The first became
extinct in the forties, and the latter was lastly seen in 1973 in the region but is still present in Azilal. These forests
still host a limited population of Lynx serval, possibly the Hyena, and a relict population of Berber deer. With relative
abundance we still found Foxes, Jackals, Wild Boars and finally the world’s last large population of the Barbary
macaque (Macaca sylvanus).
Fossil evidences show that macaques were distributed during the Pleistocene all around the Mediterranean, as far
east as the Caspian sea and as north as England (Delson, 1980, Camperio Ciani, 1986). Since then, they
underwent a severe decline correlated with habitat loss. Historically they have progressively disappeared from
Sardinia, Egypt, Tunisia, and Spain (except Gibraltar). At present are confined to the High and Middle Atlas, and a
few relict populations in the Rif forest of Morocco and the mixed forest in the Djurjura in Algeria (Fa et al. 1984;
Menard & Vallet, 1993, Camperio Ciani, 1986).
Concentration of bio-diversity
In these forests a large concentration of bio-diversity can be found compared to northern temperate forest
ecosystems. Here the forest tree composition can reach 40 different species and a variety of herbs and shrubs up
to 300 (Drucker, 1984) while in European forests this value is ten time less. A whole range of birds, reptiles,
invertebrates contribute to make these forests a unique and largely still unknown reservoir of biodiversity
EXPLORING FEMALE SEXUAL PREFERENCES WORLDWIDE: GYNEPHILIA, NON-HETEROSEXUALITY AND FLUIDITY
No full textAbstract
Introduction
Social influences and a lack of clear self-awareness might hinder women from openly disclosing their non-heterosexual orientation. Implicit methods may offer more dependable data in such cases.
Objective
This study explored non-heterosexuality and gynephilia in a large, worldwide sample of women, using both implicit and explicit methods. Implicit measures would exhibit consistency across different cultures, while explicit measures were anticipated to vary due to social influences.
Methods
A total of 491 women were recruited via an online platform to partake in this cross-sectional study. Each participant, expressed consent to partecipate, completed a brief biographical questionnaire, the Autobiographical-Implicit Association Test (A-IAT), the Sexual Preference-Implicit Association Test (SP-IAT), and an explicit measure of sexual orientation. These responses were analyzed to investigate explicit sexual orientation and implicit gynephilia across six major geographical regions (Middle East and Africa, South America, North America, Asia, Europe, and Oceania). In the subsequent phase, 263 participants completed a new implicit sexual orientation measure (Autobiographical Sexual Orientation-Implicit Association Test, ASO-IAT) and provided information on their sexual behaviors through two questions. Additionally, participants were asked about their subjective assessments of the stimuli presented in the SP-IAT.
Results
Implicit measures revealed a higher prevalence of gynephilia (67.8%) compared to explicit non-heterosexuality (19.6%), with consistent findings observed across continents. These results imply that women may experience attraction towards other women even if it doesn’t always translate into a desire for sexual encounters. Furthermore, the findings indicate a notable degree of sexual fluidity within the female population.
Conclusions
Compared with explicit assessments of non-heterosexuality, implicit measures appear to be less influenced by social factors. However, while androphilia is a prerequisite for non-heterosexuality in men, gynephilia is not necessarily a proxy of non-heterosexuality in women. Women also reveal a greater propensity for sexual fluidity than men
Gene flow by selective emigration as a possible cause for personality differences between small islands and mainland populations
No full textWhether personality differences exist between populations is a controversial question. Even though such differences can be measured, it is still not clear whether they are due to individual phenotypic responses to the environment or whether they have a genetic influence. In a population survey we compared the personality traits of inhabitants of an Italian archipelago (the three Egadi islands; N=622) with those of the closest mainland population (Trapani area; N=106) and we found that personality differences between small populations can be detected. Islanders scored significantly lower on the personality traits of openness to experience and extraversion and higher on conscientiousness. We suggest that these personality trait differences could be an adaptive response to a confined socio-environmental niche, genetically produced by a strong, non-random gene flow in the last 20–25 generations, rather than the flexible response of islanders to environmental variables. To test this hypothesis, we compared subsets of the islander population classified by ancestry, birthplace, immigration and emigration and found that differences in extraversion can be accounted for by gene flow, while openness to experience and conscientiousness can also be accounted for by some gene–environment interactions. We propose a Personality Gene Flow hypothesis suggesting that, in small isolated communities, whenever there is strong, non-random emigration, paired with weak and random immigration, we can expect rapid genetic personality change within the population
Macaca sylvanus
No full textThe Barbary Macaque is the only surviving primate in Africa north of the Sahara desert, the only native species of primate to occur in Europe, and the only member of the genus Macaca that can be found outside Asia. The species was once an inhabitant of parts of Europe and all of North Africa (Delson 1980; Camperio Ciani 1986). In historic times it was it was widespread throughout north Africa from Libya to Morocco, but its current distribution is limited to small relict patches of forest and scrub in Algeria and Morocco (Fa 1984; Camperio Ciani 1986; Menard and Vallet 1993; Scheffrahn et al. 1993). A semi wild population lives in Gibraltar, which is a long established introduced population (Fa 1981; von Starck 1990; Hodges and Cortes 2006).
In Morocco, M. sylvanus can still be found in the Rif mountains (northern Morocco) and the Middle and High Atlas mountains (central and southern Morocco). In Algeria, it is found in the Tellian Atlas (Petite Kabylie and Grande Kabylie mountains, and an isolated population in the Chréa National Park) (northern Algeria). More specifically, in Morocco the High Atlas populations (two anciently separated populations) are found in the Bou Tferda valley to Demnat region and around the Ourika Valley, respectively; the Rif populations are primarily on Mounts Lakraa, Tissouka, Tazoute, Bouhacham, and Djebel Moussa. In Algeria, from west to east, Barbary Macaque populations are distributed as follows: (a) Chiffa gorges (Chréa National Park); (b) Djurdjura forests and rocky cliffs (Djurdjura National Park, Grande-Kabylie); (c) Akfadou forests, including a small ‘subpopulation’ recently settled in degraded forests and maquis, near El-Kseur (Grande-Kabylie and Petite-Kabylie); (d) Cap Carbon, Aiguades and Pic des Singes (Gouraya National Park; Béjaïa, Petite-Kabylie); (e) Chaabet-el-Akhra Gorges (Kherrata; Béjaïa, Petite-Kabylie); (f) ‘Massif des Babors’ forests (Sétif and Béjaïa, Petite-Kabylie); (g) Guerrouch forest (Taza National Park; Jijel, Petite-Kabylie). Additionally, a Barbary Macaque population might still occur in Djebel Bouzegza (Boumerdes, Grande-Kabylie) (F. Belbachir pers. comm. 2007)
Worldwide study reveals fluid sexual preferences in females and no association between gynephilia and non-heterosexuality
No full textBACKGROUND: Social factors and a lack of clearself-awareness may prevent women from explicitly reporting their non-heterosexuality, and implicit measures could provide more reliable data. AIM: This study examined non-heterosexuality and gynephilia in a large, global sample of women using implicit and explicit methods. METHODS: A sample of 491 women participated in this cross-sectional study. Participants completed a biographical questionnaire, the Autobiographical-Implicit Association Test, the Sexual Preference-Implicit Association Test (SP-IAT), and an explicit measure of sexual orientation. In a follow-up study, 263 participants were recontacted and completed the Autobiographical Sexual Orientation IAT and answered additional questions about their sexual behavior and preferences related to the stimuli on the SP-IAT. OUTCOMES: The main outcome measures were D-scores on implicit association tests and scores on explicit measures of sexual orientation and behaviors. RESULTS: Implicit measures showed a higher rate of gynephilia (67.8%) than explicit non-heterosexuality (19.6%), with consistent results across continents. The findings suggest that women may be attracted to other women without necessarily desiring sexual encounters with them. Furthermore, the results suggest a degree of fluidity in sexual preferences in the female population. CLINICAL IMPLICATIONS: Studying the prevalence of gynephilia and non-heterosexuality in adult women can inform the development of health promotion programs tailored to women's diverse sexual experiences and preferences. STRENGTHS & LIMITATIONS: Strengths include the global sample and the use of both implicit and explicit measures. Limitations involve the cross-sectional web-based design, potential sample biases, and aspects related to the validity of the SP-IAT. CONCLUSION: Implicit measures of non-heterosexuality appear to be less tied to social factors than explicit assessments. In women, gynephilia may not necessarily serve as a proxy for non-heterosexuality. Moreover, women seem to exhibit greater fluidity in sexual preferences and behaviors than men
Testing evolutionary genetics of personality: Do balanced selection and gene flow cause genetically adapted personality differences in human populations?
No full textCapturing a scientific change in thinking about personality and individual differences that has been building over the past 15 years, this volume stands at an important moment in the development of psychology as a discipline. Rather than viewing individual differences as merely the raw material upon which selection operates, the contributing authors provide theories and empirical evidence which suggest that personality and individual differences are central to evolved psychological mechanisms and behavioral functioning. The book draws theoretical inspiration from life history theory, evolutionary genetics, molecular genetics, developmental psychology, personality psychology, and evolutionary psychology, while utilizing the theories of the "best and the brightest" international scientists working on this cutting edge paradigm shift.
In the first of three sections, the authors analyze personality and the adaptive landscape; here, the authors offer a novel conceptual framework for examining "personality assessment adaptations." Because individuals in a social environment have momentous consequences for creating and solving adaptive problems, humans have evolved "difference-detecting mechanisms" designed to make crucial social decisions such as mate selection, friend selection, kin investment, coalition formation, and hierarchy negotiation. In the second section, the authors examine developmental and life-history theoretical perspectives to explore the origins and development of personality over the lifespan. The third section focuses on the relatively new field of evolutionary genetics and explores which of the major evolutionary forces--such as balancing selection, mutation, co-evolutionary arms races, and drift--are responsible for the origins of personality and individual differences. Existing as a seminal work in the newly emerging evolutionary psychology field, this book is a "must-read" for anyone invested in the development of psychology as a field.
Features
* Draws theoretical inspiration from multiple disciplines, including: life history theory; evolutionary genetics; molecular genetics; developmental psychology; personality psychology; and evolutionary psychology
* Chapter contributors include the best and the brightest international scientists working on the paradigm shift of evolutionary psychology
* A seminal work in the newly emerging evolutionary psychology fiel
Human Homosexuality: A Paradigmatic Arena for Sexually Antagonistic Selection?
No full textSexual conflict likely plays a crucial role in the origin and maintenance of homosexuality in our species. Although environmental factors are known to affect human homosexual (HS) preference, sibling concordances and population patterns related to HS indicate that genetic
components are also influencing this trait in humans. We argue that multilocus, partially X-linked genetic factors undergoing sexually antagonistic selection that promote maternal female fecundity at the cost of occasional male offspring homosexuality are the best candidates capable of explaining the frequency, familial clustering, and pedigree asymmetries observed in HS male proband families. This establishes male HS as a paradigmatic example of sexual conflict in human biology. HS in females, on the other hand, is currently a more elusive phenomenon from both the empirical and theoretical standpoints because of its
fluidity and marked environmental influence. Genetic and epigenetic mechanisms, the latter involving sexually antagonistic components, have been hypothesized for the propagation and maintenance of female HS in the population. However, further data are needed to truly clarify the evolutionary dynamics of this trait
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