Academic literature on the topic 'Secondary sexual characteristics'
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Journal articles on the topic "Secondary sexual characteristics"
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Herman-Giddens, Marcia E., Lily Wang, and Gary Koch. "Secondary Sexual Characteristics in Boys." Archives of Pediatrics & Adolescent Medicine 155, no. 9 (September 1, 2001): 1022. http://dx.doi.org/10.1001/archpedi.155.9.1022.
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Greil, Holle, and Heidrun Kahl. "Assessment of developmental age: cross-sectional analysis of secondary sexual characteristics." Anthropologischer Anzeiger 63, no. 1 (March 11, 2005): 63–75. http://dx.doi.org/10.1127/anthranz/63/2005/63.
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Breathnach, C. S. "The secondary sexual characteristics of the brain." Irish Journal of Psychological Medicine 7, no. 1 (March 1990): 59–63. http://dx.doi.org/10.1017/s0790966700017067.
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AbstractIn the avian cerebrum and in the spinal cord, sympathetic ganglia, hypothalamico pre-optic area and cerebral cortex of the rat sexually dimorphic' nuclei are clearly recognisable. Similar differences have been described in the human brain. Morphometric analysis has shown a sexually dimorphic nucleus in the pre-optic area. There is continuing controversy over differences in the size and shape of the corpus callosum, but there is accumulating evidence of cerebral asymmetry with more focal representation of language and praxic functions in the left cerebral hemisphere in females. The various sensory modalitites also show gender differences. The significance of these secondary sexual variations in brain structure resides in the developmental and behavioural characteristics of the underlying neural circuits.
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Wojciechowski, A. P. "Evolutionary aspects of mammalian secondary sexual characteristics." Journal of Theoretical Biology 155, no. 2 (March 1992): 271–72. http://dx.doi.org/10.1016/s0022-5193(05)80598-3.
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ITO, Madoka, and Seiichi WATANABE. "SECONDARY SEXUAL CHARACTERISTICS OF METACRANGON ANGUSTICAUDA(DE HAAN)." Researches on Crustasea 21 (1992): 107–11. http://dx.doi.org/10.18353/rcustacea.21.0_107.
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Graham, E. A., N. Sugar;, S. J. Emans, F. Biro;, M. E. Herman-Giddens, E. J. Slora, R. C. Wasserman, and G. G. Koch. "Secondary Sexual Characteristics and Menses in Young Girls." PEDIATRICS 101, no. 5 (May 1, 1998): 949–50. http://dx.doi.org/10.1542/peds.101.5.949.
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Hockham, Leon R., and Michael G. Ritchie. "Female secondary sexual characteristics: appearances might be deceptive." Trends in Ecology & Evolution 15, no. 11 (November 2000): 436–38. http://dx.doi.org/10.1016/s0169-5347(00)01963-7.
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J�rvi, Torbj�rn, Eivin R�skaft, Morten Bakken, and Brigitta Zumsteg. "Evolution of variation in male secondary sexual characteristics." Behavioral Ecology and Sociobiology 20, no. 3 (March 1987): 161–69. http://dx.doi.org/10.1007/bf00299729.
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Emerson. "Vertebrate Secondary Sexual Characteristics-Physiological Mechanisms and Evolutionary Patterns." American Naturalist 156, no. 1 (2000): 84. http://dx.doi.org/10.2307/3079033.
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Emerson, Sharon B. "Vertebrate Secondary Sexual Characteristics—Physiological Mechanisms and Evolutionary Patterns." American Naturalist 156, no. 1 (July 2000): 84–91. http://dx.doi.org/10.1086/303370.
Full textDissertations / Theses on the topic "Secondary sexual characteristics"
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Christensen, Kathrine Rose. "Links between Sexual Health Content and Teacher Characteristics in North Dakota's Secondary Schools." Thesis, North Dakota State University, 2013. https://hdl.handle.net/10365/27235.
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Numerous studies indicate the ineffectiveness of abstinence-only education in preventing teen pregnancies and the spread of sexually transmitted infections (STIs), yet many U.S. schools still rely on abstinence-only programming. North Dakota, the focus of this study, neither prevents nor requires contraception instruction in sexual health education classes, leaving the decision to include contraception instruction and other sexual health information up to the individual schools and teachers. For this study, a survey of sexual health teachers was used to determine the content of sexual health classes, teacher characteristics, and links between the two. Results indicate that teacher beliefs in program efficacy impact what content is included in class, which suggests the need to provide evidenced based training and continuing education for sexual health teachers.
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Peters, Marianne. "The role of male secondary sexual traits in human mate choice : are they preferred by females and do they signal mate quality ?" University of Western Australia. School of Psychology, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0201.
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[Truncated abstract]Judgements of physical attractiveness are thought to reflect evolved preferences for a high quality mate. The central aim of this thesis was to investigate the hypothesis that female preferences are adaptations for finding good quality mates and that faces and bodies signal honest information about mate quality. To date, most human mate preference studies have examined face or body attractiveness alone, and many have created stimuli using computer graphic techniques. Throughout these studies, I endeavoured to maximise the biological relevance of my studies by incorporating both face and body attractiveness, and using photographs of individual participants. Most research on attractiveness has focused on faces or bodies separately, while our preferences have evolved based on both seen together. A fundamental requirement of studying face and body attractiveness independently is that there is no interaction between the two. My first study confirmed that the face and body did not interact when an overall attractiveness judgment was made. I also investigated the independent contributions of rated attractiveness of the face and the body to ratings of overall attractiveness. Face and body attractiveness each made significant independent contributions to overall attractiveness in males and females. For both sexes, facial attractiveness predicted overall attractiveness more strongly than did body attractiveness, and this difference was significant in males. ... This study indicates that although current levels of T covary with male mating success, this effect may not be mediated by women's preferences for visual cues to T levels conveyed in static face or body features. The fourth study in this thesis investigated the phenotype-linked fertility hypothesis, which proposes that females obtain reliable information on male fertility from male expression of sexual traits. A previous study of Spanish men reported that facial attractiveness was positively associated with semen quality. I aimed to determine whether this effect was widespread by examining a large sample of Australian men. I also extended my study to determine whether cues to semen quality are provided by components of attractiveness: masculinity, averageness, and symmetry. I found no significant correlations between semen quality parameters and attractiveness or attractive traits. While male physical attractiveness may signal aspects of mate quality, my results suggest that phenotype-linked cues to male fertility may not be generalised across human populations. Together, these studies challenge current methodologies and theories of preferences for secondary sexual traits as honest signals of mate quality. The findings show that it is important to study human mate preferences in biologically relevant contexts, for example by using photographs of both faces and bodies, to maximise the real life application of results. In addition, the findings suggest that male attractiveness does not signal cues to testosterone or semen quality, although testosterone is associated with mating success. The implications of these findings and possible avenues for future research are discussed.
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Li, Han-Yun, and 李涵芸. "Association between Secondary Sexual Characteristics and Urinary Alkylphenol Levels." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/03833960705110952243.
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碩士國立陽明大學
環境衛生研究所
95
Alkylphenols (APs), mainly composed of nonylphenol (NP) and octylphenol (OP), are known as environmental hormone. 2,4-Di-tert-butylphenol (BP) is widely used as additives and antioxidants in plastic, rubber and surfactants. Because of widely uses of APs, population in Taiwan may ubiquitously expose to the hormone-like APs. Studies have reported that nonylphenol can accelerate the onset of puberty of female rats, but the effects of NP upon adolescent human are unknown. Adolescent students are at a rapidly physical and sexual development period. This study assessed whether APs exposure affects sexualidy development in human at the age of puberty. Participants were students recruited elementary school and junior high school from northern, central, southern and eastern Taiwan. Urine samples, and information on demographic data, diet preferences and sexualities development status of each participant were collected. We recruited 378 junior high school students (grade 1 and 2) and 408 elementary school students (grade 5 and 6). In male students self-reported sexuality development status, 50.0% got pimples, 40.4% got voice changing, 39.6% got body hair growing, 36.3% had facial hair, 34.7% had an Adam’s apple, 32.4% became wider shoulders and 18.9% had nocturnal emission. In the results of female students’ reports, 86.5% had breast development, 66.4% got pimples, 61.2% appeared body hair, 55.6% experienced first menstrual cycle, 29.3% became wider hips, 28.8% showed subcutaneous fat increasing, and the average age of fist menstruation was 11.5±0.9 years old. The average urinary NP, OP and BP levels of elementary school students ranged from 1.61 to 8.64, 2.19 to 16.14 and nd to 2.43 μg/g creatinine, respectively. Those of junior high school students ranged from 0.90 to 2.19, 0.53 to 2.47, and 0.75 to 1.39 μg/g creatinine, respectively. Logistic regression analysis showed NP affected the age of girls’ fist menstruation, but no other effects on sexualities development were seen. Comparing to other study populations, urinary NP levels of adolescent students were relatively lower. This study established valuable information on urinary AP levels for Taiwanese adolescent students. Since the commonly APs exposure among Taiwanese, follow-up monitoring was needed to realize the potential cumulative effects on reproductive system.
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Tsai, Tai-Chen, and 蔡岱蓁. "Association Between Phthalate Esters Exposure and Secondary Sexual Characteristics for Pubertal Students." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/36281440032090880357.
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碩士國立陽明大學
環境與職業衛生研究所
101
Phthalates are synthetic chemicals that are used in numerous consumer products. People may be exposed to them when they use these products or via contaminated foodstuffs. Exposure routes include ingestion, inhalation and dermal contact. Several animal studies have demonstrated that phthalates can adversely affect male and female reproductive systems. They are endocrine-disrupting chemicals (EDCs), potentially interfering with the normal functions of human hormones, affecting the onset of pubertal development. This cross-sectional study aims to evaluate levels of exposure of adolescent students to phthalates. Two hundreds and ninety-three adolescent students (aged from 10 to 14) were recruited from northern, central, southern, and eastern Taiwan. Their demographic data were collected using questionnaires; urine samples were also collected. In this study we measured four phthalate monoesters including monoethyl phthalate (MEP), monobutyl phthalate (MBP), mono-2-ethylhexyl phthalate (MEHP) and monobenzyl phthalate (MBzP) were analyzed by isotope dilution and gas chromatography-mass spectrometry (GC-MS). Urine samples were deconjugated and then solid-phase extraction and GC-MS. The most frequently occurring of secondary sexual characteristic was having pimples (57.2%); the second most frequently occurring was the development of pubic hair development (50.0%). For girls, the most frequently occurring secondary sexual characteristic was breast development (87.9%), which was followed by having pimples (74.5%), and menarche (68.8%).The average age for menarche was 11.6±1.1 years. The geometric mean concentrations of MEP, MBP, MEHP, and MBzP in the urine samples of the students were 5.26, 33.37, 8.26, and 0.88 μg/g cr, respectively. The concentrations of the four metabolites, except that of MEHP, were highest in students from northern Taiwan, and were 12.4, 44.16, 9.57, 1.44 μg/g cr, respectively. According to regression models, after adjusting for age, BMI, sleeping and exercise habits, the subjects with the third quartile of MEHP concentration exhibited a significantly lower occurrence of pimple than the reference group of girls (OR=0.26, p=0.04). The menarcheal age was significantly reduced in the group with the fourth quartile of MEHP concentration and for girls with MBzP above the median concentration (β= -0.68 years, p=0.01; β= -0.57 years, p=0.00). The menarcheal declined as the PAEs metabolite concentrations increased. The group with the highest HMW PAEs concentration, had a 0.89 year earlier menarcheal age (p<0.0001). For boys, high MEP concentration was associated with a significantly higher occurrence of voice change than in the reference group (OR=3.06, p=0.01). The onset of voice change was significantly higher for the group with the highest LMW concentration than for the reference group (OR=3.80, p=0.02). A significant inversed relationship existed between LMW concentration and nocturnal pollution (OR=0.15, p=0.01). This study finds the relationship between exposure to PAEs and the sexual development of boys and girls. PAEs may reduce menarcheal age and have an estrogen-like effect on girls. This finding warrants future study to elucidate the causal relation and the associated mechanism. The effects of PAEs on the age of maturation and health require further investigation.
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Yang, Meng-Huan, and 楊孟桓. "Organophosphate Pesticide Exposure and Its Association with Secondary Sexual Characteristics of Adolescent Students." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/98289033736921069675.
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碩士國立陽明大學
環境與職業衛生研究所
100
A large amount of organophosphate pesticides (OPs) is used throughout Taiwan, and human may be exposed through dietary intake or residential use. Adolescent students are at a rapidly physical and sexual development period, they may be more susceptible to the potentially adverse effects of pesticides than other age groups. Environmental chemicals may affect the growth and development in human, but the effects of OP upon adolescent are unknown. The aim of the present study was to assess the association between OPs exposure and secondary sexual development of adolescent students. Adolescent students (N=293) aged from 10 to 14 years were recruited from northern, central, southern, and eastern Taiwan. Urine samples were collected and a structured questionnaire was also filled out by the subject to collect the demographic data. Urinary metabolite of organophosphate pesticides were assessed using gas chromatography-mass spectrometry. The analytes included dimethylphosphate (DMP), dimethylthiophosphate (DMTP), dimethyldithiophosphate (DMDTP), diethylphosphate (DEP), diethylthiophosphate (DETP), and diethyldithiophosphate (DEDTP). The highest occurrence of secondary sexual characteristic for boys was having pimples (57.3%), followed by pubic hair development (51.3%). The highest occurrence of secondary sexual characteristic for girls was breast development (88.7%), followed by having pimples (75.2%), and menarche (68.8%).The average age of menarche occurred at 11.5±1.0 years. We found that the detection rate of OP urinary metabolites for our subjects ranged from the lowest of 20% for DEDTP to the highest of 93% for DMTP and DEP . Regression analysis showed that risk factors of OP exposure included sex , urban , eating out frequency , fruits and vegetables purchase supermarkets. Regression analysis showed a significantly association between OP exposure and facial hair development in boys, association between OP exposure and pubic hair development as well as menarche in girls. Since the common OPs exposure among Taiwanese, a large longitudinal study is warranted to examine the relationship between OP exposure and secondary sexual development for adolescent students .
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Yang, Shang-Han, and 楊尚翰. "Regional Differences of Nonylphenol for Taiwanese Pubertal Students and its Correlation with Secondary Sexual Characteristics." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/52397944391481791202.
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碩士國立陽明大學
環境與職業衛生研究所
102
4-Nonylphenol (NP) is industrial chemical substance used widely in our daily products. It is also an endocrine disruptor. The structure of nonylphenol is similar to estrogen. Once inside the human body, it disrupts the original function of hormone, including changes in puberty growth. This study aims to determine regional differences of nonylphenol for Taiwanese pubertal students and to clarify its correlation with development of secondary sexual characteristics. Four hundreds and twenty-three adolescent students (aged from 10 to 14) were recruited from northern, central, southern, and eastern Taiwan. Their demographic data were collected using qustionnaires, their urine samples were also collected to analyze the NP concentration in their bodies. Urine and beverage samples were purified and assessed using high-performance liquid chromatography coupled with fluorescent detection. The highest occurrence of secondary sexual characteristic for boys was having pimples (49.0%), followed by pubic hair development (41.0%). The highest occurrence of secondary sexual characteristic for girls was breast development (71.7%), followed by having pimples (59.5%), and pubic hair (54.6%). The average age of menarche occurred at 11.4±1.0years. This research also studied the secondary sexual characteristics of adolescent schoolchildren of different ages in northern regions. The result showed that there were significant differences in the secondary sexual characteristics of the male students of 2008 and that of 2012. Adolescent boys in the 2008 study had a higher occurrence rate of secondary sexual characteristics than their 2012 counterparts. As for female students, the rate of appearance of pubic hair and menstrual during 10 to 12.99 of age is higher in the 2012 adolescent female students. Compared to their 2008 counterparts, their age of menarche also appeared to be lower. Except for the growth of pubic hair and occurrence of menstrual, other rate of sexual characteristics of the 2012 students were generally lower than those of 2008. In addition, the mean concentration of urinary NP of the students were 4.97±4.27, 3.50±2.94, 3.37±2.49, and 3.34±2.72μg/g creatinine, from northern, central, southern, eastern, respectively. According to regression models, after adjusting for age, BMI, sleeping, exercise habits and region, the results showed that exposure to nonylphenol was a risk for the advancement of menarche of age for girls. The menarcheal age decrease as the NP concentration increase. The above-median group had a 0.20 year earlier age of menarche. Regression analysis showed a significant association between age and pubic hair development in girls. BMI is significantly associated with the occurrence pimple, pubic hair, widening of hips, and menstruation in girls (OR=1.10；1.22；1.10；1.23). Sleeping hour is not associated with secondary sexual characteristics. The odds ratio of breast development for central and southern girls (OR=6.11;3.77) are higher than northern counterparts. Since NP exposure is quite common among Taiwanese, a large longitudinal study is warranted to examine the relationship between NP exposure and secondary sexual development for adolescent students .
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Lin, Zi-liaung, and 林子量. "Potential Factors Influencing the Development of Secondary Sexual Characteristics in Adolescent Students: Surrounding Environment, Diet and Living Habits." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/73185118316233385979.
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碩士國立陽明大學
環境與職業衛生研究所
97
Most of the research data of secondary sexual characteristics of pubertal student in Taiwan concentrate in the beginning of female menarche, so this research contains the self-administration questionnaires of whole Taiwan elementary and junior high school students from 5 to 8 to realize the status and potential factors of secondary sexual characteristics. Secondary sexual characteristics refers the difference of the appearance, figure, face and voice exclusive of reproductive organ. Boy’s Secondary sexual characteristics of this research are acne, the Adam’s apple, pubic hair, armpit hair, facial hair, nocturnal emission and voice change. Girls Secondary sexual characteristics of this research are acne, breast, pubic hair, armpit hair, subcutaneous fat, buttocks and menarche. By stratified random sampling, we retrieve 956 effective questionnaires which have 493 boys and 463 girls from whole parts of Taiwan. The Responding rate is higher than 90%. According to the results, ages, heights, weights and most secondary sexual characteristics have strong positive correlation. Taking Secondary sexual characteristics as dependent variables and taking ages, body mass index, tonic supplements , sleeping, exercise, urban/rural area ,and total scores of meat-protein as independent variables to analyze the potential factors shows that Ages have significant correlations on boy’s Acne, the Adam’s apple, pubic hair, armpit hair, girl’s acne, pubic hair, armpit hair and menarche. Tonic supplements have significant correlations on girl’s pubic hair, armpit hair and menarche. Besides, comparing with former research, we find that the coming age of menarche becomes lower in each grade. And according to the result of logistic regression shows that students having tonic supplements have greater opportunity on the present of menarche pubic hair and armpit hair than others, and the ORs rate are 2.75 and 1.88 respectively. This result maybe related to tonic supplements which containing growth hormone which promote the growth of body. Boys who have longer time on exercise have greater opportunity on the present of acne and this maybe related to personal health. In addition, we find that students who sleeping between 6~8 hrs have greater opportunity on the present of acne. So far, because there is no research concentrate to discuss the issue about having tonic supplements cause effect on girl’s secondary sexual characteristics, we can research focus on the population of having tonic supplements in the future. For example, designing case-control or cohort study to observe that whether proportion of having tonic supplements is higher than controls or not. Finally, we will continue to detect the pesticide in urine of pubertal students for the further environment’s effect on secondary sexual characteristics.
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PECH, Michal. "Vliv syntetického progestinu etonogestrelu na sekundární pohlavní znaky a histologii gonád živorodky Wingeovy (Poecilia wingei)." Master's thesis, 2019. http://www.nusl.cz/ntk/nusl-396084.
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Synthetic progestins are steroid hormones, which are not only part of the hormonal contraceptives, but they are also used to treat a number of health problems in human. Due to the widespread use of progestin-based drugs, their residues are being found in wastewaters, from where they also enter into the wastewater treatment plants and surface waters. The aim of this thesis was to assess whether the synthetic progestin etonogestrel affects the secondary sexual characteristics and gonad histology of Endler´s guppy (Poecilia wingei). During the experiment, males and females were separately exposed to 3.2 and 320 ng.l-1 etonogestrel for 34 days. A group of fish reared in pure water (K) and group of fish reared in pure water containing the solvent dimethylsulfoxide (KS) served as controls. At the end of the test, all the fish were photographed to capture any color changes. Then the fish were sacrificed and fixed in 10 % buffered formalin solution for morphometric and histological analysis. Fish samples taken for morphometric analysis were photographed using QuickPHOTO MICRO 2.3 software and individual morphometric parameters were measured on the images taken. Fish sample processing for histological analysis included decalcification, dehydration, and pouring of the samples into paraffin blocks. Then paraffin blocks were cut with the thickness of about 4.5 um, resulting slides were stained with hematoxylin and eosin. Histological changes of the gonads were determined on the histological samples prepared in this way. In females exposed to both concentrations of etonogestrel occurrence of color spots was observed. Color spots are characteristic for male and in females indicate masculinization. In addition, females exposed to 320 ng.l-1 etonogestrel showed a change in anal fin morphometry to a gonopodium-like structure (modified anal fin of males serving as helping copulatory organ), a sign also suggesting masculinization. Furthermore, exposure of etonogestrel in both lower and higher concentration of etonogestrel reduced number of mature oocytes in the ovaries, and their occurrence decreased with increasing concentration. In males exposed to both concentrations of etonogestrel a smaller ratio of the length of 4th ray to the length of 6th ray of gonopodium was found. In addition, at concentration of etonogestrel 320 ng.l-1 a greater ratio of the length of 6th ray to body length and extension of length of 6th ray was observed. Although there were no changes, which would indicate hypermasculinization, these changes could have a negative impact on reproduction, or sexual selection by the female. Etonogestrel exposure had no effect on the normal development of testes, because predominantly mature spermatophores were found in males of all treatment groups. Based on these findings, we can say that etonogestrel, like other progestins, represents a real risk to fish if it occures in aquatic environment at concentrations reaching units of ng.l-1.
Books on the topic "Secondary sexual characteristics"
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Slater, Jonathan A., Katharine A. Stratigos, and Janis L. Cutler. Child, Adolescent, and Adult Development. Oxford University Press, 2014. http://dx.doi.org/10.1093/med/9780199326075.003.0014.
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The development of children and adolescents is characterized by abrupt discontinuities as well as continuous aspects of behavior such as individual temperament. The crucial task of the first year of life is the development and solidification of the attachment between infant and caretaker. Toddlers and adolescents tend to experience intense conflicts around autonomy and control that become resolved as they progress in the process of separation-individuation. The tasks of middle childhood include developing a sustained sense of mastery and competence, morality, and stable self-esteem; as ego functions grow and consolidate, children become increasingly able to tolerate frustration and delays in the gratification of their wishes and desires. Adolescence begins with puberty, the period of sexual maturation in which the primary sex organs develop and become capable of reproduction and secondary sex characteristics appear. Although adolescents tend to engage in risk-taking behaviors, the majority of adolescents maintain normal academic and social functioning; an adolescent whose rebelliousness includes severe disturbances in conduct, mood, or drug abuse should be evaluated for possible psychopathology requiring treatment. The main social developmental tasks for adults take place in the realms of work and intimate relationships.
Book chapters on the topic "Secondary sexual characteristics"
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Dekker, M. L., C. A. Hinde, and B. J. A. Pollux. "Secondary Sexual Characteristics." In Encyclopedia of Evolutionary Psychological Science, 1–4. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-16999-6_65-1.
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Dekker, M. L., C. A. Hinde, and B. J. A. Pollux. "Secondary Sexual Characteristics." In Encyclopedia of Evolutionary Psychological Science, 6890–93. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-319-19650-3_65.
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Sever, David M., and Nancy L. Staub. "Hormones, Sex Accessory Structures, and Secondary Sexual Characteristics in Amphibians." In Hormones and Reproduction of Vertebrates, 83–98. Elsevier, 2011. http://dx.doi.org/10.1016/b978-0-12-374931-4.10005-7.
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Sever, David M., and Nancy L. Staub. "Hormones, Sex Accessory Structures, and Secondary Sexual Characteristics in Amphibians." In Hormones and Reproduction of Vertebrates, 83–98. Elsevier, 2011. http://dx.doi.org/10.1016/b978-0-12-374932-1.00018-4.
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Butler, Gary, and Jeremy Kirk. "Puberty and its disorders." In Paediatric Endocrinology and Diabetes, 49–82. Oxford University Press, 2020. http://dx.doi.org/10.1093/med/9780198786337.003.0002.
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• Puberty is defined as the acquisition of secondary sexual characteristics, with a view to reproductive capability. • Assessment of puberty can be done by Tanner stages or the puberty phases. • Timing of pubertal onset and sequence of changes is carefully controlled. • Premature sexual maturation: ◦ <8 years in girls; menarche <11 years ◦ <9 years in boys. • Central precocious puberty or gonadotropin-dependent precocious puberty: ◦ hormone secretion is similar to normal puberty ◦ may be idiopathic, genetic, or secondary to central nervous system/pituitary tumour or insult ◦ treatment is with gonadotropin-releasing hormone analogues. • Gonadotropin-independent precocious puberty (independent source of sex steroid, e.g. gonadal tumour): ◦ treatment should address the primary cause. • Late puberty: ◦ pubertal events within the later normal range. • Delayed onset of puberty: ◦ absence of secondary sexual characteristics: ■ >13 years in a girl ■ >14 years in a boy • Central causes (low follicle-stimulating hormone (FSH)/luteinizing hormone (LH)): ◦ chronic illness ◦ eating disorders ◦ physiological ◦ hypogonadotropic hypogonadism. • Peripheral causes (high FSH/LH): ◦ gonadal dysgenesis including chromosomal syndromes, e.g. Turner, Klinefelter ◦ gonadal damage including cancer treatments. • Treatment: ◦ low-dose sex hormone to induce growth and secondary sexual characteristics ◦ recombinant FSH/LH to induce fertility potential.
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Simmons, Leigh W. "3. Choosing from the field of competitors." In Sexual Selection: A Very Short Introduction, 34–51. Oxford University Press, 2018. http://dx.doi.org/10.1093/actrade/9780198778752.003.0003.
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There is now unequivocal evidence for Darwin’s long-rejected suggestion that females choose among potential mates based on their secondary sexual traits. This has shifted attention from the question of whether females exercised mate choice, to why they should exhibit the mating preferences they do. ‘Choosing from the field of competitors’ gives a contemporary view of mate choice and its occurrence in a wide variety of animal species, along with some examples of what females are choosing and why parasites and disease may play a role in the evolution of extravagant secondary sexual characteristics. Several theoretical models are discussed along with the role of sexual selection in the evolution of humans.
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Srinivas-Shankar, U., and F. C. W. Wu. "Disorders of male reproduction." In Oxford Textbook of Medicine, 1913–27. Oxford University Press, 2010. http://dx.doi.org/10.1093/med/9780199204854.003.130802.
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Luteinizing hormone (LH) stimulates biosynthesis of androgenic steroids by binding to specific surface membrane receptors on the Leydig cells in the testis. Testosterone is essential for male sexual differentiation, growth and function of the male genital tract, secondary sexual characteristics, sexual potency, and production of spermatozoa....
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Mcphaul, Michael J., and Richard J. Auchus. "Sexual Differentiation." In Textbook of Endocrine Physiology. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199744121.003.0010.
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Sexual differentiation is a sequential process that begins at fertilization with the establishment of chromosomal sex, continues with the determination of gonadal sex, and culminates in the development of secondary sexual characteristics that comprise the male and female phenotypes. This basic paradigm was formulated by Alfred Jost to explain the results of castration experiments in fetal rabbits. If the gonads (ovaries or testes) were removed before sexual differentiation, female sexual differentiation inevitably ensued. The male pathway could be partly restored by testosterone implants, suggesting that hormones produced by the testes mediate male sexual development. Thus, the concept arose that the testes induce a male pattern of differentiation on an embryo that otherwise would follow the female pathway. Cytogenetic studies shortly thereafter showed that the critical genetic determinant of sex is the presence or absence of the Y chromosome, leading to the proposal that the Y chromosome directs the gonad to differentiate into a testis, which then produces hormone(s) that cause male sexual differentiation. The chromosomal sex of the embryo generally corresponds to its phenotypic sex. Occasionally, however, the process of sexual differentiation goes awry, resulting in individuals with disorders of sexual differentiation (DSD). Clinically recognized disorders of sexual development occur at many levels, ranging from relatively common disorders in the terminal steps of male differentiation (e.g., testicular descent, growth of the penis) to more fundamental abnormalities that lead to varying degrees of ambiguity of phenotypic sex. Although most of these abnormalities impair reproduction, they usually are not life threatening. Thus, humans and experimental animals with naturally occurring defects in sexual differentiation survive to reach the attention of physicians and scientists. This chapter reviews the sequence of events in normal sexual development and describes disorders of this process — many of which result from single-gene mutations — that have provided valuable insights into the mechanisms of sexual differentiation. Normally, human somatic cells have 22 pairs of autosomes and 1 pair of sex chromosomes.
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Bouloux, P. M. G. "Disorders of male reproduction and male hypogonadism." In Oxford Textbook of Medicine, edited by Mark Gurnell, 2386–406. Oxford University Press, 2020. http://dx.doi.org/10.1093/med/9780198746690.003.0252.
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The adult testis performs two principle functions: the synthesis and secretion of androgens, and the production of male germ cells, the spermatozoa. Testosterone is essential for male sexual differentiation, growth, and function of the male genital tract, secondary sexual characteristics, sexual potency, and production of spermatozoa. Hypogonadism may be due to disorders of the pituitary/hypothalamus (secondary or hypogonadotropic hypogonadism) or testes (primary or hypergonadotropic hypogonadism). Its symptoms and signs depend on the age of onset of androgen deficiency. Prepubertal presentation is with sexual infantilism, delayed puberty, and eunuchoidal body proportions. Male infertility may affect 5% of men of reproductive age and is caused by a heterogeneous group of disorders. The commonest cause (60% of cases) is ‘idiopathic’ azoo/oligozoospermia, although many cases are now recognized as due to discrete gene defects associated with impaired spermatogenesis. Other causes include cryptorchidism, testicular tumours, genital tract infection, obstructive azoospermia, and sperm autoimmunity.
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Palmer, Neal A., Joseph G. Kosciw, Emily A. Greytak, and Madeline J. Boesen. "Disrupting Hetero-Gender-Normativity." In Sexual Orientation, Gender Identity, and Schooling, 58–74. Oxford University Press, 2016. http://dx.doi.org/10.1093/med:psych/9780199387656.003.0004.
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For lesbian, gay, bisexual, and transgender (LGBT) youth, schools are often sites of exclusion and victimization. Research has demonstrated that LGBT youth experience elevated rates of victimization and bullying at school relative to their peers, but less research has explored the contexts and characteristics of schools that enable negative attitudes and behaviors toward LGBT youth. The authors examine how US schools construct environments that are unwelcoming and unsafe for LGBT students and largely fail to provide the supports that could improve the school learning climate. They examine strategies and practices employed by educators, students, and education advocates that can disrupt hetero- and gender-normative practices in schools. Specifically, we examine the mechanisms by which LGBT-related school supports—gay–straight alliances (GSAs), comprehensive anti-bullying/harassment school policies, supportive educators, and LGBT-inclusive curricula—support students’ well-being and academic success and challenge the hetero- and gender-normativity embedded in US secondary schools.