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pivoxa15
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At what stage in the human reproductive system is the sex (i.e. XY or XX) determined?
arildno said:When the sperm cell joins with the egg.
The sperm cells come in two types, X and Y-cells.
The egg cell only carries the X-chromosome.
That's what he means. The male's sperm determines the sex of the fertilized egg by virtue of the fact is carries either an X or Y chromosome, which then pairs with the X chromosome in the egg.pivoxa15 said:I thought X and Y are associated with chromosomes only. Do you mean two types of cells, one carrying the X chromosome and the other Y chromosome?
Yes, chromosome pairs in males are XY, while in females they are XX.pivoxa15 said:So this would imply each cell of a female and male is different? All these tiny differences at the cell level make up the macro difference we observe.
pivoxa15 said:I thought X and Y are associated with chromosomes only. Do you mean two types of cells, one carrying the X chromosome and the other Y chromosome?
Astronuc said:That's what he means. The male's sperm determines the sex of the fertilized egg by virtue of the fact is carries either an X or Y chromosome, which then pairs with the X chromosome in the egg.
Yes, chromosome pairs in males are XY, while in females they are XX.
http://en.wikipedia.org/wiki/Chromosomes#Human
http://www.madsci.org/posts/archives/may98/896252107.Ge.r.html" that explains fetal sexual development and the differences between phenotypic and genotypic sex.reasonmclucus said:I don't have time to find a link for the following.
Normally, that is the case, but it is possible for a person with two "X" chromosomes to develop as an anatomically correct male. The individual is not able to produce viable sperm -- or at least those XX males who discovered their genetic defect because of infertility are.
It is also possible for someone with an XY pair to develop as a female. This condition can run in families and often the vagina does not have an adequate connection to the uterous. It appears a genetic defect prevents the fetus from knowing how to develop male sexual features.
These individuals think of themselves as being of their anatomical sex rather than their genetic sex.
Other individuals are born with both male and female genitals. Some experts suggest that premature decisions about which physical sex these individuals are may create problems later if they belief they are of the sex associated with the genitals that were removed. In other cases the reason a person believes himself or herself to be of the other anatomical sex is unclear, but there is a theory that it involves develpment of the brain.
A key point is 'normally'. I wonder, it this because one X chromosome in the XX pair is faulty, or the Y in and XY pair is faulty, which certainly could happen.reasonmclucus said:Normally, that is the case, but it is possible for a person with two "X" chromosomes to develop as an anatomically correct male. The individual is not able to produce viable sperm -- or at least those XX males who discovered their genetic defect because of infertility are.
It is also possible for someone with an XY pair to develop as a female. This condition can run in families and often the vagina does not have an adequate connection to the uterous. It appears a genetic defect prevents the fetus from knowing how to develop male sexual features.
I imagine that is how most people develop, unless one's genetics are tested.reasonmclucus said:These individuals think of themselves as being of their anatomical sex rather than their genetic sex.
The term with which I am familiar is 'hermaphroditism'. And there are genetic anomalies such as XXY and XYY, but I believe such occurrences are rare.reasonmclucus said:Other individuals are born with both male and female genitals. Some experts suggest that premature decisions about which physical sex these individuals are may create problems later if they belief they are of the sex associated with the genitals that were removed. In other cases the reason a person believes himself or herself to be of the other anatomical sex is unclear, but there is a theory that it involves develpment of the brain.
Sex determination in humans occurs at the moment of conception, when a sperm from the father fertilizes an egg from the mother. The baby's sex is determined by the presence or absence of a Y chromosome in the sperm, which determines whether the embryo will develop into a male or female.
Yes, sex determination can be determined before birth through various prenatal genetic tests such as amniocentesis or chorionic villus sampling. These tests can detect the presence or absence of a Y chromosome in the baby's DNA and determine the baby's sex.
Sex determination in humans occurs at the moment of conception and does not change throughout the pregnancy. However, the external genitalia of the baby may not fully develop until around the 12th week of pregnancy, making it possible to determine the baby's sex through ultrasound at that time.
Both genetics and environment play a role in sex determination in humans. The presence or absence of a Y chromosome in the sperm determines the baby's sex, while hormonal and environmental factors can affect the development of the baby's external genitalia.
While the baby's sex is determined at the moment of conception, the individual's gender identity may not align with their assigned sex at birth. In these cases, individuals may undergo gender reassignment surgeries and hormone therapy to change their physical appearance and align it with their gender identity.