My dad wasn't sure I was his, until I was in my sixties. He and my mother never mentioned that, but it does explain a lot of their behaviour towards me. Even though my child looked so much like his own father he had to put her photos away because he felt his dad was 'watching' him, he wasn't sure!
Dad agreed to a dna test to checkout his Irish ancestry (came out 'Roscommon' which is pretty specific). Later I had my own dna tested to see if there was anything I should know about my mother's side.
In conversation, I mentioned that my ancestry pages state 'His Name is your father.' I was very surprised when he immediately got up from where he was sitting and demanded 'Show me!' We weren't any closer once he'd seen the truth in writing, but that's ok.
A year or so ago, I was shopping in a local supermarket when an old man came up to me and said 'I knew your mother!' Not being particularly sociable, and having known my mother well, I replied coldly 'My mother knew a lot of people.'
'She did!' he responded 'I could be your father!' 'Well, you're not,' I said firmly, 'My dad and I are dna tested, my dad is definitely my dad.' And I walked away, having no interest whatsoever in some old bloke who'd shagged my mum early in 1957.
This week, another old bloke came up and demanded to know if was Dad's Name's daughter. Yes, I am. He wanted to tell me about some work he'd had done by Dad, still going well fifty years later. Or so he said. Instinct tells me he's another one. Mum...honestly!