why men are men and women are women?

Answer 1

men have xy chromesome and women have an xx.

as default we all develop as women and at some point in development(in womb) the ovarys become testes ect ect ect if the sex chromosome is xy

Answer 2

Chromosomes (really tightly wound DNA) generally determine sex. Humans have 23 pairs of chromosomes, and get one of each from each parent. The 23rd pair is referred to as the sex chromosomes because a pair of XX chromosomes causes a female-sexed individual to develop and an XY pair (usually) causes a male to develop. I say "usually" beacuse there are a number of smaller genes involved in the development of a male fetus that, if faulty or nonfuctional, can interfere with how well male characteristics develop.

Furthermore, there are very fundamental changes in brain chemistry that occur early in the fetus' development, and the more obvious changes that occur during puberty, resulting in secondary sex characteristics (facial hair in men, breast development in women, etc).

And, of course, there are trans-gendered individuals who may feel that their identities differ from the sex they were born with, but this is a very complex psychological and biochemical realm that is not yet well-understoood.

Answer 3

It's one of the mysteries of evolution why most complex animals have sexual reproduction instead of just cloning. There are two leading theories at the moment:
- without sexual reproduction, a species evolves too slowly to adapt to environmental changes
- sexual reproduction creates genetic variation, thereby confusing parasites

More research is needed.

Answer 4

Simply Y chromosome! SImply X chromosome.

Answer 5

Boys have a penis, girls have vaginas....