I definitely fall into this category... But I've never had a problem admitting it! Everyone, my family included, knows that the main reason I will never, ever produce a child from my body is that I refuse to pass on my genetics to anyone. To a degree, that includes my health problems, but it also includes a fear that I will be the same sort of BNP (breeder not parent) that my mother is and my sister is.
My mother, addicted to morphine after a serious accident before we were born, allowed her parents to adopt us when we were just babies.... This sounds fairly self-sacrificing, right? Doing the right thing for her children? Well, my maternal grandparents, who adopted my mother privately when every single adoption agency in the state of Texas turned them down due to my grandmother's mental instability, were not fit to raise goldfish, much less children. My grandfather wasn't so bad, but my grandmother did 90% of the raising of us, and she's the one who's nuttier than squirrel turds. My mother left home because of the way my grandmother treated her... And my mother regularly rants about how screwed up she is because of my grandmother. But when she wanted her freedom, she gave us up to them without blinking, and then went her merry way, rarely seeing us, and even when she made arrangements to see us, she rarely kept her word.
My sister got knocked up and married the guy (ironically only months after I had an abortion)... He was the first of two husbands, and her son from that marriage was the first of five pregnancies.... She has had three live births (she has custody of none of her children... Her oldest was taken away by the father and the courts refused to give her custody back, the second girl was given up for adoption, and she named a man who wasn't the father of the third girl on the birth certificate and signed away her parental rights to her to that man and his wife <apparently they were friends and couldn't afford adoption>)... and an abortion and a miscarriage. Rumors are that there was a second abortion, but she's never confirmed that. She does whatever she wants to do without thought to anyone else, including her children. She's selfish, self absorbed, irresponsible, immature and negligent when it comes to her personal affairs.
I'm not perfect... I set out to make some really stupid life choices early on. I was exceptionally promiscuous, I partied hard, without thought to anything... I [censored] away college, managed to acquire a drug addiction, and nearly died twice. I was at least smart enough to be "selfish" enough to have an abortion when I DID get pregnant, and aware enough that I didn't want children to make sure it didn't happen again. I've managed to get my life together... I cleaned up, beat the addiction (eleven years!!) and got married to a great guy. He's supported me through everything (we've been friends almost ten years longer than we've been a couple, 20 years altogether), and supports me in my decision not to have children (my family is example enough for him, lol). HIS family is amazing, and supportive, too. I have several serious, genetically hereditary health conditions that I don't want to pass on, either, so my decision is pretty much carved in stone not to ever get pregnant.
If the winds change (I doubt it, but I always make room for change) and we decide that our life is empty without children, we'll adopt. We like our life how it is right now, so I doubt we'll be doing even that.