I'm not one of them, but my half-brother is. I was 16 and my mother approached me and told me for the first time I had another brother I never heard of that she was forced to give up for adoption. She was telling me then because he was turning 18 that year and she was confident he would look her up and that they could reunite. Never happened.
She told me one day (later when providing more details and I asked) that she had originally had an abortion and she thought she was no longer pregnant. She still has no idea what happened. She didn't have her period months before pregnancy because of malnutrition, and she never gained weight during her pregnancy at all. So the absence of all that, and the abortion done, she thought she wasn't pregnant until the end a few weeks before he started coming much too early.
Her water broke and she was laying down on the living room floor and asked her mother what was happening. Her mom wanted to go and see her new boyfriend so just told my mom it meant she would have a dry birth, then left her there. She ended up getting herself to the hospital and they stopped the birth for awhile because it was too early but everything was okay at the end after extended hospital stays.
So, she did have an abortion, but she ended up still being pregnant after the procedure was done. She's mystified but thankful about it. It could be there was a twin, I really have no idea, it doesn't make much medical sense. She had no help, was dirt poor, and had little medical care so there's no telling. Maybe they even just told her they did an abortion and took the money at the clinic but forgot to do it. We'll never know.
I was born 2 years later. She was with my father at the time who was a good man who was able to get her out of a horrible, abusive existence. My brothers father took off on her when she was pregnant and she wasn't able to take care of herself and it was dangerous circumstances. When I came around she had more stability and help from my father.
She said she named him Robert and he had curly type blonde hair and beautiful eyes. Her pregnancy with me was also pretty rough, I was early, and she almost died from anemia again. She had my other brother ten years later, and they had to put something in her cervix and had weekly appointments because they worried she wouldn't be able to carry him full term due to cervical cancer issues in her early twenties. Thankfully it all went fine and her body was able to carry him full term.