The physical differences are undeniable. The sex chromosome of humans are called X and Y. A zygote that receives an X chromosome from each parent is a genetic (XX) female, whereas a zygote that received a Y chromosome from the father is a genetic (XY) male.
The X and Y chromosomes carry genes that determine many other traits. Genes situated on the X and Y chromosomes are therefore known as sex-linked genes. So far, the majority of the sex linked genes are located in the X-chromosome. These are known as X-linked genes.
Chromosomal differences result in different prenatal hormone balances in male and females, and hormones are responsible for the facts that the genitals of males and females differ and only female can bear children.
Moreover, males typical grow to be taller, heavier and more muscular than females, while females may be the hardier sex in that they live longer and less susceptible to many physical disorders.
Females tend to be 10 percent smaller than male in most physical variables such as heart size, blood volume and hemoglobin concentration. However, females also carry approximately twice the body fat of males.
The brain weight in an ‘average’ female is about 100 g less than in the male. Much was made of this to prove the lesser intellectual capacity and ability of a woman, until it was recognized that the range in brain weights of adults is very great, and that proportions, male and females differ less in brain weight than a total body weight.
Male and females: physical differences
