I've had this thing since I was little that I just gravitate toward femininity when given the chance.
When I was 12, when my mom was first leaving me alone at home, I (through a self dare) tried on my mom's bra and a flood of "girly" feelings came to me that was so wonderful I couldn't deny that I loved it. It started years and years of cross dressing and me exploring my feminine / girly / womanly feelings.
I first tried on a woman's long wig 14 years ago and upon seeing myself in the mirror, what I saw staring back at me was the real me.
I can allow myself to talk with my "real" voice and my voice in a short while automatically becomes very feminine (I did train my voice long ago, but it doesn't click unless I am allowed to feel female.)
I do exercises where I'm allowed to "feel free" and "feel light", and always I start automatically acting very feminine. When in a friendly environment, I start using feminine gestures without thought.
Seven years ago, when I was going to TG clubs, I "tricked" myself into believing that I was always living as a woman, and in that mental state I felt totally female and I acted feminine virtually automatically, and I had the spirit of a fun, bubbly, feminine young woman. It's one of the biggest things that depresses me when I remember it.
I've never been interested in having sex as a male. My idea of sex for the longest time really had been just kissing and foreplay. Never actually really doing it (other than embarrassment that I was still a virgin.) Upon allowing myself to explore the idea of having sex as a woman about at least 12 years ago, I absolutely loved it, loved it to the point that all my fantasies gravitated toward being the bottom (with a vagina) and I feel so wonderful when imagining myself being penetrated.
I don't think its about whatever gender I feel, I believe I'm more of an outside-in, that my outside influences what gender I feel, but that from long experience I gravitate toward being female, and so much of me is female, and I'd much rather prefer feeling female. In addition, I feel like that since I am a feeler, and am naturally emotionally sensitive (despite years of trying to kill off emotions when I was younger), that the male gender is a hostile place to be, vs the female gender being accommodative and even supportive of emotional freedom. I can't tell you how much I yearn to be in a supportive environment, and being in a gender that is supportive of who you are means a lot to me.