The phrase "in your blood" suggests that some people might be wired, genetically, to crossdress. That's difficult to prove--although many transsexuals make that claim, and indeed some children know very early that they're gendered incorrectly. It's a nature/nurture question that is still unsettled among experts because gender is partly a social construct and partly physiological.
For most of us the impulse to crossdress is learned behavior that probably began at an impressionable moment when we were young, or later on. In that sense it's a "bug" we caught, and for many of us has become chronic.
