Is there some assumption on here that we all chose to conceive a child when in fact the intention was to have a good time? That's how it went with us. Loved my son dearly as a chld and continue to do so now that he's an adult. Stop thinking about it too much, cut loose, have a few drinks and go through the shock of the positive pregnancy test, the discussion about whether to keep 'it', the acceptance of the relationship, the joy of the birth, the bonding with your darling boy, the break up with his mother and making the effort to be the best absentee father possible. Feel vindicated by having the respect and love of your son when he could choose to not to want to know you. Or you could just be responsible.