Child's Play Theories

Who is Tiffany's sister?

So Tiffany's sister really isn't a number one topic in the "Child's Play world" but there is an scene in Seed Of Chucky Where Tiffany says "once is a blessing twice is a curse" and Chucky replies "well that would explain your sister"

And then her sister is never brought up or even mentioned again. I know that means Tiffany's sister is obviously not an important character and is probably not even in Tiff's life anymore. But that still makes me wonder..who is her sister? And what was the point of Chucky mentioning her?

I'm thinking maybe her sister is someone outside the Chucky universe. I think her sister hates violence and the idea of killing. That would explain why Glen is like that.

Who knows? Maybe her sister is a character in a Nickelodeon show with the last name Valentine.

But..this is just a theory and is not a fact. Until her sister is finally revealed we can come up with anything..