I had a dream that was based sometime after Final Fantasy 7 (interesting how i have awesome dreams about it even though I've yet to play it).
I was the daughter of Cloud Strife and Tifa; but Tifa had Jenova cells in her body, which meant:
A. She was kind of like a sister to Sephiroth.
B. She had powers similar to his.
C. Those powers were genetically passed down to me.
My brother and I were awake before the crack of dawn for some odd reason. All of a sudden, the window behind us crashes as Sephiroth flies in with the intent to kidnap me. But my brother pushes me out of the way and lets himself be taken instead.
At the break of dawn, Tifa takes me outside and reveals her secret to me: that she has Jenova cells just like Sephiroth does, and, therefore, has the ability to shape-shift. She tells me not to follow her, lets me know she loves me, and transforms into a giant dove/eagle awesome bird thing. She then flies off after Sephiroth to go save my brother.
Despite my mother's wishes, I venture off to seek the aid of Cloud's old allies and receive training that will help me go after Tifa, confront Sephiroth, and save my brother.
Dunno where Cloud was during all this, but I'm guessing he was an estranged father.