The desire to be your target gender may vary over time, as Lost explains:
"There are cycles and mini cycles. Throughout a normal day I will get small ups and down, and there are bigger and more extreme waves that take place over months. I would go months content with my own occasional fantasies, to suddenly feeling compelled to seek out every single TG type of material I can possibly find."
Debate over at CDL: Does the Intensity of Your Crossdreaming Come and Go? Do You Know Why?