Potters Fall for Redheads

It's a proven fact. Potters do fall for the redheads; James for Lily and Harry for Ginny. Why is this? I have not a clue, and I don't really plan on answering that question. But what I will look into is how one Potter broke the chain of "redheaded women". Previously posted on another site, this is the reincarnation and eventual completed version. SM/RW, ASP/OC