Fragile X Syndrome is a genetic disorder that is caused by a mutation in the FMR1 gene on the X chromosome. Since boys have only one X chromosome, while girls have two, they are more likely to be affected by the syndrome. This is because if a boy inherits the mutated gene, he does not have a second healthy X chromosome to compensate for the mutation. Girls, on the other hand, have a second X chromosome that may carry a healthy copy of the gene, reducing the chances of developing Fragile X Syndrome. Therefore, the condition shows up more in boys.