Re: A dilemma...
Life as I know it is generally steeped with regrets and with hindsight the desire to turn back the hands of time to do things differently...
Seize the day...you have the opportunity of meeting your birth father, perhaps for the last time. Yes, he is just an old man to you and yes there may be no emotional attachment on your part. However, he has expressed a desire to contact you despite knowing that you have little or no recognition of your relationship with him. This if nothing else, is testimony that there is at least still some emotional attachment on his part, give the guy his dues for still trying
If you are adamant that you don't want to reestablish any continuous contact , perhaps you should see him and finally close this chapter once and for all. See him, say what needs to be said, get things out in the open and clear the air. At least then you can walk away from him knowing that nothing was left unaddressed. Thereon perhaps, for you it wouldn't matter if you never saw him again...