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Name: Mike
Status: educator
Age: 40s
Location: N/A
Country: N/A
Date: 2000-2001

If a parent has chromosomal abnormalities (such as a father with an XYY genotype) are their children at a higher risk of having chromosomal abnormalities as well?

They are. Since half his sperm will have two chromosomes in it, either an XY or a YY there is a 50% chance of inheriting and extra chromosome (XXY or XYY). This is because the mother will contribute an X. At anaphase I the XYY will divide into either XY and Y sperm, or YY sperm and X. At fertilization, the mother gives an X, so the child can be: XXY or XYY or XY or XX

So 50% chance of extra chromosome, and 50% chance of normal.


Up-date 9/5/2005

Since this answer was given, new information has been published about the fate of the children of Kleinfelters fathers. Probability would say that there is a 50-50 chance of inheriting an abnormal gamete. But new research shows that this is not the case in reality. The following link is to a paper written on this topic. It turns out that only 1% of the gametes turn out to be abnormal. This raises new questions, as often happens in science. For example, why? Where do the other gametes go? Science is a process that is always subject to revision as new information becomes available.


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