A bad birth experience, actually. Not mine, though, my ward-sisters. She gave birth in an army hospital (I was her official "birth coach"
and the doctor want her to choose between having me and having her husband there for the actual birth! ??? We said "Uh, no" so they rolled her in to the delivery room instead, because there wasn't enough room in the LDR for all of us
, and although she avoided a c/sec, it was absolutely horrible - like perfection perverted. I felt like I was watching her get raped, although she now says things like "Oh, just think how much worse it would have been without the episiotomy!" You know, the one that tore into a third degree...
That started me researching, and I found that midwifery perfectly combined my interests in holistic medicine (my mom's a family practice MD, and I loved the caring for people part of her job growing up), feminism, activism, linguistics, sex (I grew up in a household where vulva and penis were regular words, knew the basics about most forms of birth control by the time I was seven, and never understood the concept of sex and genitals as "dirty" and "not to be discussed in polite company"), and, well... I fell in love with pregnancy and birth. Long before I even resolved the issue of whether I wanted any children of my own.
I suppose really it started before that, though, because I grew up hearing the story of my own wonderful birth (my mom had me in an Alternative Birth Center, and told me all about pushing me out with no meds, putting me right to the breast so she didn't need pitocin, and taking a nap with the three of us - mom, me, and dad - on the double bed afterward), so I grew up with the fundamental knowledge that birth could equal pleasure, or at least pleasant memories.