Sociology Index

SEXUAL DIMORPHISM

Sexual dimorphism is the differences between males and females in size and appearance. Sexual dimorphism in humans is greater than in some animals and less than in many. Evolutionary psychologists and biologists are intrigued to understand the function of sexual dimorphism. Depression is twice as common in women as in men, but the reason for this sexual dimorphism is unknown.

Pelvic Politics: Sexual Dimorphism and Racial Difference - Sally Markowitz, Signs, Vol. 26, No. 2 (Winter, 2001).

Snips and Snails and Theorists' Tales: Classical Sociological Theory and the Making of 'Sex' - Exploring how the emerging discipline of sociology both drew on and contributed to the construction of a scientifically grounded sexual dimorphism.
Barbara L. Marshall, Trent University, Canada.

This article locates classical sociology within the context of widely circulating scientific 'truths' about sexed bodies, exploring how the emerging discipline of sociology both drew on and contributed to the construction of a scientifically grounded sexual dimorphism.

Through an examination of Durkheim's theory of conjugal society and Weber's writings on the routinization of sexual conduct, the extent to which anxieties about masculine sexuality animated classical conceptions of the shifting mind/body relationship in modernity is illuminated.

Normal Sexual Dimorphism of the Adult Human Brain Assessed by In Vivo Magnetic Resonance Imaging 
Jill M. Goldstein, Larry J. Seidman, Nicholas J. Horton, Nikos Makris, David N. Kennedy, Verne S. Caviness, Jr, Stephen V. Faraone and Ming T. Tsuang
The etiology and consistency of findings on normal sexual dimorphisms of the adult human brain are unresolved. In this study, we present a comprehensive evaluation of normal sexual dimorphisms of cortical and subcortical brain regions, using in vivo magnetic resonance imaging, in a community sample of 48 normal adults. Sexual dimorphisms of adult brain volumes were more evident in the cortex, with women having larger volumes, relative to cerebrum size, particularly in frontal and medial paralimbic cortices. Men had larger volumes, relative to cerebrum size, in frontomedial cortex, the amygdala and hypothalamus. A permutation test showed that, compared to other brain areas assessed in this study, there was greater sexual dimorphism among brain areas that are homologous with those identified in animal studies showing greater levels of sex steroid receptors during critical periods of brain development. These findings have implications for developmental studies that would directly test hypotheses about mechanisms relating sex steroid hormones to sexual dimorphisms in humans.

Regulation of Sexual Dimorphism in Mammals 
CHRISTOPHER M. HAQQ AND PATRICIA K. DONAHOE 
Pediatric Surgical Research Laboratories, Massachusetts General Hospital, and Department of Genetics and Surgery, Harvard Medical School, Boston, Massachusetts 
Haqq, Christopher M., and Patricia K. Donahoe. Regulation of Sexual Dimorphism in Mammals. Physiol. Rev. 78: 1-33, 1998. Sexual dimorphism in humans has been the subject of wonder for centuries. In 355 BC, Aristotle postulated that sexual dimorphism arose from differences in the heat of semen at the time of copulation.

Sexual Dimorphism in Counterregulatory Responses to Hypoglycemia after Antecedent Exercise - Pietro Galassetti, Anthony R. Neill, Donna Tate, Andrew C. Ertl, David H. Wasserman and Stephen N. Davis 
Departments of Medicine and Molecular Physiology and Biophysics, Vanderbilt University School of Medicine and Nashville Veteran Affairs Medical Center, Nashville, Tennessee 37232-6303 
Abstract: After antecedent hypoglycemia, counterregulatory responses to subsequent hypoglycemia exhibit greater blunting in men than in women. Because physical exercise and hypoglycemia share multiple counterregulatory mechanisms, we hypothesized that prior exercise may also result in gender-specific blunting of counterregulatory responses to subsequent hypoglycemia. Thirty healthy subjects (15 women and 15 men; age, 28 � 3 yr; body mass index, 23 � 1 kg/m2) were studied during 2-d experiments. In summary, two bouts of prolonged, moderate exercise (90 min at 50% maximum oxygen expenditure) induced a marked sexual dimorphism in key neuroendocrine (glucagon, catecholamines, and muscle sympathetic nerve activity) and metabolic (glucose kinetic, lipolysis) responses to next day hypoglycemia.

Age, Gender, and Non-modulation - A Sexual Dimorphism in Essential Hypertension 
Naomi D. L. Fisher; Claudio Ferri; Cesare Bellini; Anna Santucci; Ray Gleason; Gordon H. Williams; Norman K. Hollenberg; ; Ellen W. Seely - From the Departments of Medicine, Harvard Medical School and Brigham and Women's Hospital, Boston, Mass, and Universit� La Sapienza, Rome, Italy. 
Abstract The angiotensinogen gene is one of the very few related by linkage analysis to human hypertension, but the linkage has been consistently shown only among males. Moreover, polymorphisms in this gene predict an abnormal renal responsiveness to angiotensin II, a feature of non-modulation, but again, only among males. To pursue these related bridges between genetics and physiology, we evaluated the effects of sex on a second feature of non-modulation, the aldosterone response to infused angiotensin II during low sodium balance. We tested the resultant hypothesis—that non-modulation would be less frequent in women—by conducting identical protocols on 225 hypertensive inpatients (70 women, 155 men). Non-modulation was strikingly less frequent among women (26%; 95% confidence interval, 16% to 37%) than men (49%; 95% confidence interval, 40% to 57%) (P=.001).

Childhood Sexual Abuse as a Risk Factor for Depression in Women: Psychosocial and Neurobiological Correlates 
Erica L. Weiss, M.D., James G. Longhurst, M.D. and Carolyn M. Mazure, Ph.D. 
OBJECTIVE: Depression is twice as common in women as in men, but the reason for this sexual dimorphism is unknown. This article reviews recent studies of the role of childhood sexual abuse in the subsequent development of major depressive disorder, and the biological and psychosocial mechanisms by which early stressors may contribute to adult-onset depression in women. Particular attention is paid to investigations of the long-term effects of early stress on hypothalamic-pituitary-adrenal (HPA) axis function.

Brain Development, XI, Sexual Dimorphism - JILL M. GOLDSTEIN, PH.D., DAVID N. KENNEDY, PH.D. and Verne S. CAVINESS, JR., M.D., D.PHIL., Boston, Mass. 
The size of the human brain is established at a young age, much earlier than motor, psychological, or cognitive maturity. Whole brain volume is at 95% of its adult size by 4 years of age. However, the brain continues to develop well through the teen years, including alteration of the relative volume of brain regions, neuronal number, synaptic connections, and neurochemistry. A number of these changes are sex specific. In the adult human brain, although the overall cerebral size is larger in men, several regions are proportionately larger in women, including the caudate nucleus, hippocampus, some prefrontal cortical areas, the superior temporal gyrus, and some white matter structures such as the anterior commissure. Example, the prepubertal volume of cortical gray matter is greater than its adult size, particularly in boys. In contrast, prepubertal white matter volume develops faster in girls than in boys. Sexual brain dimorphism results, in part, from hormones that affect neuronal formation and elimination and glial development.

Sexual dimorphism in humans.