Click on the link below for the diagram showing the ancestors from whom women and men can inherit their X-DNA. X-DNA can be inherited from the people who are colored in. If the person is not colored pink or blue, you cannot inherit X-DNA from them. Use the circle on the left if you are a man; use the circle on the right if you are a woman.
Also keep in mind that FamilyTree DNA (FTDNA) might over-estimate your X-DNA matches. Make sure to examine those matches in the chromosome browser on FTDNA. That will remove DNA segments under 5 cM.