Yeah, never had an awakening. I'm not sure I always had a *pregnancy fetish* per se, versus gradually growing into it, but it's always been something I was at least open to, and I can definitely take a couple guesses why.
First off, it's just a statistical fact that men with younger siblings at a certain age gap--and were thus exposed to their pregnant mothers during certain developmental periods--are more likely to be into pregnancy. I have a 3 years younger sister, who I supposedly even *asked for*, and although I don't have any conscious memory of the pregnancy I know she was a stay at home mom and I was a very needy autistic toddler so we must have spent quite a bit of that time together. (I'm told I wasn't even fully weaned at that point...) I think I actually do remember that it took them some effort to stop me from watching her give birth, and that may have contributed to a fascination with the matter.
My porn/masturbation journey in general... I can still remember the smell of my first nocturnal emission, and after that I know I dry humped the bed and such, but I don't think I started properly masturbating with my hands until I was 10 or so. I had long been well aware of what porn was and where to find it, but had also fully internalized that it was not for kids and could really fuck you up, so I was deathly afraid of it to the extent that I was interested at all. It was only after I happened to stumble into some or another nude painting or sculpture while doing a fifth grade research project that I built my first ever spank bank entirely out of what was available on Wikimedia Commons--in the form of memorized category hierarchies, because I felt so dirty and guilty if I actually *typed* the word "nude".
I gradually broadened the horizons of what I was willing to scar myself with into female masturbation, then the scant sapphic material available there, then drawings of anal and fellatio (I also remember rather embarrassingly that some time before this, I was reading an article about STD transmission rates, and gleefully exclaimed, "It's so funny how they call kissing 'oral sex'!"), then drawings of penis-in-vagina, then finally the surprisingly large collection of amateur straight porn uploaded by the kinds of weirdos either delusional enough to think there's an educational use for it or just that determined to get it out there, before graduating to pixiv with the occasional fearful excursion onto PornHub... but before any of that, there were only so many pictures of women in varying states of undress (not sure if I was actually straight at the time or if I just wasn't open to men on a more conscious level), so I couldn't really get picky and did find myself already developing my tastes in a fetishistic direction in order to remain titillated within those constraints.
And then also my family's just fucking weird. Lots of codependent emotional incest type bullshit, zero shielding from adult knowledge. I don't think I ever didn't know what sex was and how it worked, but I was given the impression that it was just a joyless and disgusting way to make babies. I never got to see my parents model normal, healthy intimacy, or really any intimacy at all, so even long before the divorce they may have even outright told me that the full extent of their relationship was that they got along well enough to make me and they still got along well enough to work together to raise me. Both of them were and are pretty sex-negative, but even on an emotional level things were pretty distant between them (mom's depressed and anxious, dad's almost certainly a narcissist), if not with me. I was the center of their world--*everything about me* was the center of *our* world. And I mean everything.
My earliest exposure to pregnancy might not have even been seeing my mom pregnant with my sister... It might have been seeing her pregnant with me. So, so many maternity photos. They never hesitated to talk about it. Where they met, how they named me, how she stopped her bipolar meds to keep them out of my fetal bloodstream, how long the labor took, how tall I was and what they injected me with after what exact minute of the morning I was born at what hospital--I think they may have even shown me the disposable paper bracelet they gave her as a patient, which they kept as a keepsake. I almost recall them showing me photos of my umbilical cord, clamped and ready to cut. He made up a lullaby, he sang me a goddamn lullaby, about how cute I already looked as I came "down the chute". The vivid mental imagery of my mother's vagina was far too familiar for me to have the slightest inkling it ought to be disturbing by the time I found it embarrassing enough to make him stop (not without some "teasing" protest from him). When we cuddled in bed, I would gravitate towards her belly if not between her legs--eventually she shut it down because it seemed too incestuous (at least she had the sense not to phrase it like that around me--I'm not sure he would have), but I think that's just where I felt at home.
So long before I was really into pregnancy, I was into birth. There was an element of non-sexual interest, and simply passive exposure, but it also sort of formed the conceptual core of my proto-sexuality the same way I imagine normal kids think about kissing and hugging and seeing each other naked. Maybe without the lullaby it would have just turned into a normal breeding kink, what with how my father would always talk not about potential "partners" or "girlfriends" but "mates"--maybe I would have been too disgusted when I found birth pictures. But I wasn't too disgusted. So much was oh so familiar, and the rest, I was curious about. I was intellectually curious to learn more, to have a clearer picture of this wonderful pivotal moment at the beginning of my life (even if I really didn't want to actually see it), and I was also just fucking horny. Enough to endure all the blood and hair and sludge, and even medical gore. Sometimes I was even in the mood for C-sections, whether it was the shape of the mother's open womb or the firm touch of the surgeons' gloved hands. I had a classmate in elementary school who I learned had been born by C-section, and in that moment I got what I thought was a crush. I would fantasize about making some grand declaration of my love for her and living the rest of our lives in each other's embrace, even though I barely knew her--because I also got it in my head that there must have been a recording of the operation for medical training purposes, and fantasized even more about finding and watching it. That was to be the foundation of any and all intimacy.
And I feel sick to my stomach every time I remember. So if anything, I'm pretty glad I can usually settle for just pregnancy these days.