Ginny and Books 6 & 7, Seventh child

[Random]

No: HPFGUIDX 69308

On Thursday, July 10, 2003, at 08:44 PM, Zen wrote:
> I've read so many posts about the "missing" Weasley son who would
> make Ron the seventh son (possibly of a seventh son).  I'm so
> pleased to see someone else wonder about the magical possibilities
> of the seventh *child*!  Ron's mentioned an aunt and a cousin at
> least, so we know that Mr. and/or Mrs. Weasely must have brothers or
> sisters someplace -- could Ginny possibly be the seventh child of a
> seventh child?  That would certainly cover the vivid red hair and
> the rapidly developing strength she's displaying.


What I want to know is where exactly the idea of the seventh child 
being powerful, etc, comes from... I've never heard of that... can 
someone provide references?

--Random832