>>81957630 (OP)It is not some deeply ingrained instinct. You did not evolve to like the color pink and frilly dresses, these things are due to "operant conditioning", that is you take a neutral stimuli and associate it with an instinct. I don't claim to be Freud, I can't psychoanalyze you and determine exactly how you made this association through the course of your life, but it must be an association of some sorts.
That's the basic theory, but it gets more complicated. Homosexual men often preferred playing with dolls as kids rather than toy cars, for example, due to their brains forming similalry to the heterosexual women. Dolls and cars are "neutral stimuli", yet girls and homosexual boys prefer dolls, the display behavior, the social aspect, the heightened maternal instinct.
So there is no true "neutral stimuli", each stimuli holds an instinctive appeal, which can then be reinforced via repetition, and this can get very confusing to someone who has developed very strong feelings on something. Long story short it often leans heavily towards neutrality. An extreme example might be showing a sexually attractive man and woman to someone who has never seen them before, but most stimuli is not like this, you have to learn to associate them with your instincts and reinforce it over many years.
The same applies to "body image", there is no reason for a heterosexual woman to evolve a particular "body image" and certainly many homosexual men are comfortable with their male bodies, the scientific evidence is quite clear on this. You need not undergo intensive psychological reconditioning to undo this however, you can't destroy memories, however you can reinforce new ones, you can find healthier ways to sate your instincts, whether sexual or other things that make you happy.