My mother had 4 kids. One with her first husband - that was an arranged marriage (part of her silly Middle Eastern culture - family brings a guy to the house, says, "Meet your husband," daughter has no choice....he can be 30 years older; doesn't matter.) She was married to him for a few months, they had a daughter, she got an annulment, left her country & abandoned her daughter when she was 5 months old. I didn't know I had a half sister until I was 16 & she came to stay with us for a few weeks. She moved to Illinois where she met my dad, married again & had 3 more kids. I'm the middle one. My older brother is what I call "An example of nature's carelessness" - a thief, scam artist, convicted felon (fraud), major dirtbag. Our mom & dad paid over $200,000.00 to keep him out of prison after he was convicted & sentenced to a year. When our parents passed, my brother didn't agree with their will & trust that divided their assets equally - he wanted everything, so he started a court battle that took 7 years & over $100,000.00 in legal fees. When it was over, he had to sell the house his mommy & daddy bought him to pay the judgement in our favor and his attorney.
While we were growing up, I'd frequently crack my dad up by saying to him: "What the hell were you & mom thinking?" and "I want DNA proof that my & my brother are related."