What are the possible genotypes of the parents?

Since the disease is X-linked, it is recessive.

1. If the mother is a carrier (XB Xb) and the father is healthy (XB Y), then there is a 25% chance that they will have a boy who is healthy (XB Y). There is also a 25% chance that there will be a girl who is completely healthy (XB XB). There is also a 25% chance that there will be a girl who is a carrier (XB Xb) and a 25% chance that there will be a boy that completely has the disorder (Xb Y).
2. If the father has the disorder (Xb Y) and the mother is a carrier (XB Xb), then there is a 25% chance that there will be a girl who is a carrier (XB Xb) and a 25% chance that there will be a girl that completely has the disorder (Xb Xb). There is also a 25% chance that there will be a boy who is completely healthy (XB Y), and a 25% chance that the there will be a boy who completely has the disorder (Xb Y).
3. If the father completely has the disorder (Xb Y) and the mother is healthy (XB XB), then there is a 50% chance that there will be a girl who is a carrier (XB Xb), and a 50% chance that there will be a boy who is completely healthy (XB Y).
4. If the father is completely healthy (XB Y), and the mother completely has the the disorder (Xb Xb) then there is a 50% chance that they will have a girl that is a carrier (XB Xb), and a 50% chance that they will have a boy that completely has the disorder (Xb Y).
5. If the father completely has the disorder (Xb Y), and the mother completely has the disorder (Xb Xb) then there is a 50% chance that they will have a girl that completely has the disorder (Xb Xb), and there is a 50% chance that they will have a boy who completely has the disorder (Xb Y).

How does a person inherit this genetic disorder? Is it dominant or recessive? Is it genetic or chromosomal?

Fragile X Syndrome is a mutation located on the FMR-1 gene. This disorder is full blown when the CGG sequence is copied more than 230 times. The sequence CGG codes for Arginine. When a person has between 54 and 230 copies of the CGG sequence they are a carrier and have no symptoms of the disorder. Although carriers have no signs of the disorder, they may pass it on to their children. A female that is a carrier for the disorder there is a 50% chance that her child will have the full syndrome and show signs of the disorder. When a person has more than 230 copies of the CGG sequence, they show signs of the disorder and can pass the disorder on to their children. When there are more than 230 copies of the CGG sequence, the FMR-1 gene is disabled. The FMR-1 gene plays a large roll in the development of the brain, so this is why many people with Fragile X Syndrome suffer from mental retardation or other mental issues. This gene is located on the X Chromosome, so Fragile X Syndrome is a X-linked disorder. Since the disease is X-linked, there are roughly twice as many males with Fragile X Syndrome as females (this includes carriers). This disease is genetic so it is passed on from generation to generation.

What is a Genetic Counselor?

Job Details
Genetic Counselors advise people on the condition of their genetic disorders. If a person with a genetic disorder wants to have a baby, then they should consult a Genetic Counselor about the chances of their kids having the genetic disorder. A parent with a child who has a genetic disorder may go to a Genetic Counselor. The Counselor will tell the parent what the chances are that their child will pass on the disorder to another generation.
Education/Qualifications
Genetic Counselors have an undergraduate degree in a science related field of study. They also have a Masters Degree in Genetic Counseling or some form of counseling.