Pretty short oneshot, for no real reason. I'm writing plenty more, but I couldn't resist putting this one onto paper.
Probably a bit of a random idea. Oh well, I'm a random person. Meh, besides, I love Wilf!

I'd be proud. If you were my father.

Strip away all the layers; the crotchety old man, the eccentric, the dandy, the grinning face, the young sportsman, the grumbling one, the snapping one, the innocent one, the bitter one, and his current self. Strip them all away and you were left with one small kernel, one tiny nugget which was, wholly, the Doctor. None of the prevarications or moods of specific regenerations, instead the essence of what each body had in common.

It was there that he placed the phrase; the memory.

He had no more time left. The TARDIS fell around him, blazing light shot from his neck and arms, energy spraying the coral. No more time; and yet he had not given a wedding gift to the happy couple. The ticket really came from Geoffrey Noble.

He did not have time.

So he made the time. The small thoughts, the command, was embedded in the centre of his consciousness. The only small seed constant between regenerations.

One hair plucked from his head; placed on the console. He trusted the TARDIS to take care of it. And then the room was flooded with regeneration; the TARDIS damaged severely. Hair charged with energy.

Days passed. He met Amy and Rory, saved Earth again. The usual stuff; all with the feeling he'd forgotten something. A gift, a final 'I forgive you'.

Then the TARDIS released the hair, and everything changed.

It crackled, emitting golden sparks. He didn't dare let anyone touch it, not even himself. The hair rested on the console for weeks; at every free moment that the Doctor had, the sonic screwdriver was run over it, buzzing, rewriting the DNA, carefully, fixing it.

Days later.

Chameleon arch brought down; rested over the hair. No fob watch however; it would not be changing back.

He touched the hair.

Light, a gentle swell, the ebb and flow of glowing air, almost aquatic. The regeneration energy infusing the hair released.

A soft cry. A completely human child; a baby. Softly crying, resting on the console.

Born from the Doctor's DNA, formed from the energy of regeneration, yet it had little in common. No similar DNA, no common memories, barely any similar characteristics save for a minute remnant of his touch. And a genuine love for Donna Noble at the genetic level. It took a special kind of person.

The child was deposited on Earth.

The wedding of Donna Noble; Wilf sat down, weary, outside the church.

The Doctor had made his last visit several minutes ago. The TARDIS departed, leaving him saddened, and Donna quite possibly rich. His last farewell to the Time Lord.

"Hello," a man sat down just beside him.

Donna's grandfather looked sideways, nodding to himself as he recognized the man. Shaun Temple; Donna's new husband.

"So, you're my father now," Shaun said after a few seconds.

"Yep, that's how I think it works," Wilf chuckled a little

"Good," Shaun stood up, nodding and smiling back at the old man. "Allons-y," he muttered. The words were odd in his mouth, yet they flowed as if he had a lot of practise.

Wilf stared after him.

"Oh my word…" he mumbled, unable to decide whether or not to be solemn, or to jump up and cheer.