In the comments of my Q&A post, Iain Quicksilver asked this question in the comments: "Does this mean my crossdreaming is an implanted fetish, or could it be she was merely drawing out something already in myself?"
This brings up the long-standing question of Nature vs. Nurture. I'm pretty sure most are familiar with this topic and anyone that has taken an Intro to Psychology course probably spent at least a week studying it at some point in time.
There are loads of case studies that provide support for either side and always a load of case studies that provide support to the contrary. With that in mind, unless they discover a gene that is "responsible" for every minute variation and quirk in every human, I have to believe that we are a factor of both nature and nurture.
Things that we experience as trauma during our formative years does have the ability to affect how we will see the world for the rest of our lives. Whether or not we are genetically predisposed to those events I cannot say.
It is my belief that childhood events are powerful but in most cases, it requires more than a singular occurrence to cause a fractured sense of self or a complete redefining of our self-image. This is the great separator when differentiating between cases of abuse. e.g. A child that is punished harshly once is disciplined. A child that regularly treated consistently harshly without merit is abused. In the former case, ideally the child creates an immediate negative association and learns to avoid that in the future. In the latter, the child likely develops a state of helplessness and confusion, where they feel like they have no control over the outcome of situations.
The original comments that preceded the question:
"When I was small, my aunt set me up for crossdreaming by telling me I
looked like a girl in a beret and then, when I didn't want to wear one,
talking my father into making me wear it. Later she caught me
masturbating and said she would tell my father. Not long after (I was
probably about three at the time), my father and I were taking a walk,
and as we rounded a corner, he stopped and said "I understand you've
been playing with yourself down there. Better stop, or you'll turn into
a girl." I was instantly filled with desire but disguised it as
embarrassment. I'm sure my aunt advised him to say that, knowing full
well what effect it would have on me. I am her creature."
I have only basic knowledge of the concept of crossdreaming, but from what I gather in its most simple definition, it is the state getting aroused at the idea of being the opposite gender (or adopting a mindset of the opposite gender).
There is a lot that can be drawn from the quoted blurb above. What I could see happening through such events has the greatest impact on views of the genders.
The aunt, who is a woman, is powerful, in control, intelligent, capable of manipulating men/boys, and inflicting pain both directly and indirectly.
The father, who is a man, is easily influenced and while physically imposing, seems much less threatening as his role is to act as her instrument.
Couple in a notion that masturbating, e.g. something done for pleasure to oneself, will inevitably lead to becoming female also creates a strange association.
I'm sure there is a lot more to this story, but that is what I would draw from what was written.
I could be wrong here, but it seems like a strong crucible for developing a timid/submissive male, confident/secure female type of a split... although as a genetic male, that sort of existence would likely result in painful/shameful crashes every time the mindset returns back to male.
With that in mind and returning to the original question, evidence points towards nurture. Whether or not something exists genetically making that more susceptible to happening, I cannot be sure, but I definitely wouldn't ignore t he possibility.