Gender Difference

GENDER DIFFERENCE

Biological Differences:

The basal metabolic rate is about 6 percent higher in adolescent boys than girls and increases to about 10 per cent higher after puberty. Women tend to convert more food into fat, while men convert more into muscle and expendable circulating energy reserves. At age eighteen, men (on average) have about 50 percent more muscle mass than women in the upper body, 10 to 15 percent more in the lower. Men, on average, have denser, stronger bones, tendons, and ligaments. This allows for heavier work.

Men dissipate heat faster than women through their sweat glands. Women have a greater insulation and energy reserves stored in subcutaneous fat, withstanding cold better, and performing better in activities requiring extraordinary endurance. Sex differences in endurance events are less significant than for sprinting events.

Men typically have larger tracheae and branching bronchi, with about 30 percent greater lung volume per body mass. They have larger hearts, 10 percent higher red blood cell count, higher hemoglobin, hence greater oxygen-carrying capacity. They also have higher circulating clotting factors (vitamin K, prothrombin and platelets). These differences lead to faster healing of wounds and higher peripheral pain tolerance.

Women typically have more white blood cells (stored and circulating), more granulocytes and B and T lymphocytes. Additionally, they produce more antibodies at a faster rate than males. Hence they develop fewer infectious diseases and succumb for shorter periods. Ethologists argue that females, interacting with other females and multiple offspring in social groups, have experienced such traits as a selective advantage.

Sex difference in Brain structure and Cognitive processes

Males possess more tightly packed and more numerous nerve cells (neurons) than females. Females tend to have more neuropil, the fibular tissue that fills the space between nerve cell bodies and contains mainly nerve cell processes (synapses, dendrites and axons) that enable neurons to communicate with numerous other nerve cells. Women are more prone to dementing illnesses than are men. The woman's functional loss may be greater because the cells lost are more densely connected with other neurons. It has been shown that a region of the hypothalamus is visibly larger in male rats than in females and that this size difference is under hormonal control. On average, men perform better than women at certain spatial tasks. In particular, men seem to have an advantage in tests that require the subject to imagine rotating an object or manipulating it in some other way. They also outperform women in mathematical reasoning tests and in navigating their way through a route. Further, men exhibit more accuracy in tests of target-directed motor skills--that is, in guiding or intercepting projectiles. Women, on average, excel on tests that measure recall of words and on tests that challenge the person to find words that begin with a specific letter or fulfill some other constraint. They also tend to be better than men at rapidly identifying matching items and performing certain precision manual tasks, such as placing pegs in designated holes on a board. In general, males are better at spatial tasks involving mental rotation.

In general, females have superior verbal skills.

Males are far more likely to pursue math or science careers, but gender differences in math are not consistent across nations or ages.

A number of imaging studies have demonstrated that the brains of males and females show different patterns of activity on various tasks.

Nicotine has been shown to differentially alter men's and women's brain activity patterns so that the differences disappear.

Both estrogen and testosterone have been shown to affect cognitive function.

Training has been shown to bring parity to differences in cognitive performance between the sexes.

Age also alters the differences between men and women.

Role of hormones in Gender Related Behaviour :

Depriving newborn males of sex hormones by castrating them or administering hormones to newborn females resulted in a complete reversal of sex-typed behaviors in the adult animals. Treated males behaved like females and treated females, like males. Studying mice, School of Medicine researchers have found that females might have a hormonal advantage for processing dietary fats. Male mice, like their human counterparts, have the capacity to respond to estrogen if it is present at high levels. Males of many species are more susceptible than females to infections caused by parasites, fungi, bacteria, and viruses. One proximate cause of sex differences in infection is differences in endocrine-immune interactions. Specifically, males may be more susceptible to infection than females because sex steroids, specifically androgens in males and estrogens in females, modulate several aspects of host immunity. It is, however, becoming increasingly more apparent that in addition to affecting host immunity, sex steroid hormones alter genes and behaviors that influence susceptibility and resistance to infection. Thus, males may be more susceptible to infection than females not only because androgens reduce immunocompetence, but because sex steroid hormones affect disease resistance genes and behaviors that make males more susceptible to infection. Consideration of the cumulative effects of sex steroid hormones on susceptibility to infection may serve to clarify current discrepancies in the literature and offer alternative hypotheses to the view that sex steroid hormones only alter susceptibility to infection via changes in host immune function. Various hormones, including sex steroids and neuropeptides, have been implicated in aggression. In this study we examined (1) sex differences in intrasexual aggression in naпve prairie voles; (2) the effects of developmental manipulations of oxytocin on intrasexual aggression; and (3) changes in patterns of intrasexual aggression after brief exposure to an animal of the opposite sex. Within 24 h of birth, infants were randomly assigned to receive either an injection of oxytocin (OT) or oxytocin antagonist (OTA) or to one of two control (CTL) groups receiving either isotonic saline or handling without injection. As adults, animals were tested twice in a neutral arena; before (Test 1) and 24 h after (Test 2) a 4-h exposure to an animal of the opposite sex. In Test 1, CTL males were more likely to show aggressive and less