How do sex chromosomes actually determine the sex of the individual?

Answer 1

The sex chromosomes are the X and the Y chromosomes. Any individual with the Y chromosome is male, because the genes that cause a zygote (fertilized egg) to develop into a male are located on this chromosome. This means that only a male can make a male.

This is because the father of a child has the combination XY and the mother has XX. This is true of all people. Each parent gives a copy of half of their chromosomes to create a baby (23 each). A man's half would be the sperm and the woman's the egg. Together the cobine fertilizing the egg and creating the developing baby which NOW, has 46 chromosomes (23 from each), the normal number.

In order for a boy thier must be one X and one Y chromosome (XY). For a girl there must be (XX). So the fater must give the Y and the mother would give an X, resulting in a boy and each parent has to give an X for a girl.

Sorry, it was hard for me to explain for someone else to understand and I apologize if you don't. Look it up on the Web. You can ask me almost any science question. (Sorry so long!)

Answer 2

Genes on the sex chromosomes (X and Y in humans and most other mammals) typically determine the physical manifestation of sexual characteristics. For example, in humans, the Y chromosome carries the SRY gene that triggers testis development as well as genes for sperm development. The sex chromosomes also affect the production and regulation of sex hormones, which are involved in physical development of both primary and secondary sex characteristics.

Note that the sex chromosomes are not the same in all organisms. Birds and butterflies have a system in which females, not males, are the heterogametic sex (males have sex chromosomes ZZ, while females are ZW). Many other organisms don't use sex chromosomes to determine sex at all.

Answer 3

If genes on the Y chromosome are expressed during fetal development in the future gonads, they become testicles. If not (if there are 2 X's) they become ovaries. The fetal testicles then produce a level of testosterone during development, which induces the rest of the reproductive anatomy to develop as male (or the ovaries do not, and the default development of the body is female).

If the number of sex chromosomes is more or less than 2, sex development will be abnormal.

Answer 4

Females have two X chromosomes. Males have one X and one Y chromosome. All eggs have one X chromosome. Sperm cell have one X or one Y chromosome. Sex of the fetus is determined by which sperm cell fertilizes the egg cell. If it is an X the fetus will be female. If it is Y the fetus will be male.

Answer 5

girls have xx cromasones and boys have xy

but the xy is olny in some sperm cells so if the xy enters the egg its a boy if the sprm cell doesent have thexy chromasone it goes of the girls egg witch is (xx)

and is a girl