Well it's always up to you if you consider your genetic parent, your "real father" - sperm donors, adoption, hospital mix-ups, affairs, early death, re-marriage blah blah. No shortage of reasons why you one of your 'parental figures' might not be 50% genetically related to you - and conversely I'm absolutely fine with anybody who rejects a genetic parent as they're an arsehole. Taking all of that in, you get to pick who cared for you and you choose to reciprocate with the parental nominative. Genetic stuff is just some nice to have information, along with what's more likely to kill you than average and how friendly your progenitors were with the local neanderthals.

I think maybe it boils down to some people always wanting to know (me) and others who don't (whatever it is) - and you've probably self-selected when you clicked all the boxes as you spat into a tube.