SEX DIFFERENCES: THE BIOLOGICAL APPROACH-CHROMOSOMES
If inadequate studies such as intelligence and personality tests cannot convince us about the differences between men*and women, perhaps the truly scientific world has the answers.
Biologists differentiate between males and females in seven main ways: i the chromosomes; 2 the sex organs; 3 the sex hormones; 4 the internal reproductive organs; 5 the secondary characteristics; 6 the gender role; and 7 sexual identification.
Chromosomes-All living organisms are made up of cells, each of which has a nucleus which contains chromosomes. These carry the genes which contain the blueprint which defines every detail of each organism’s structures and function. These genes are inherited, thus explaining how it is that physical and psychological characteristics can be passed from generation to generation. Genes control the myriad of complex enzyme systems in the body, some of which are responsible for brain and hormone metabolism — both of which probably affect behaviour to some extent. Every cell in the human body contains twenty-three pairs of chromosomes, each of which in turn carries thousands of genes. The exception to this rule are the sex cells (sperms and eggs) each of which contains twenty-three single chromosomes. When an egg is fertilised by a sperm the two sets of twenty-three link to form a complex double set which is essential for the development of a new human being.
One pair of the twenty-three pairs of chromosomes is responsible for determining the sex of the individual. Generally each chromosome matches its partner in the pair, except for the sex chromosomes in males which are different. One is called the X chromosome and the other is very small and is called the Y chromosome. A woman has two X (normal-sized chromosomes) and a man an X and a Y. So women are XX and men are XY in sex-chromosome structure. Sperms carry either an X or a Y chromosome. The sex of the baby is decided by which reaches the egg first. If this is a Y-carrying sperm, the baby will be male. An absence of a Y chromosomes produces a female even if one of the chromosomes is missing (as sometimes occurs) with an XO pattern.
Because the Y chromosome is so small it is obvious that females have more genetic material than males right from the start. There is now evidence that one of these Xs is repressed and that only one is really operative. This would make sense in that both sexes would thus tend to have roughly equal amounts of chromosomal material.
But Nature plays some odd tricks from time to time and as a result teaches us some interesting things about males and females. Many of these lessons go to prove how difficult it is to be dogmatic even about something as seemingly straightforward as whether a person is male or female.
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Categories: Men's Health-Erectile Dysfunction | Tags: Men’s Health
