Those mutated genes are most commonly recessive. Females have two X chromosomes so they can have a chromosome with the mutated gene and one with the healthy gene. The healthy gene is dominant so the disease won't manifest, and the woman is only a carrier. Males have only one X chromosome and an Y chromosome. If they have the mutated gene on the X chromosome they won't have another X chromosome with the healthy gene.
To summarize, men can't be carriers and they only need one copy of the mutated X-linked gene while women need two copies of the mutated gene.
Once the DNA of a person has been copied it can be compared to the DNA of other people by using PCR (Polymerase Chain Reaction).
Is this a serious question ? loool
