Ginny

[Carol]

Potioncat:
> I don't think it's because Ginny is a girl, after all, Molly is there, ready to fight. But Ginny is too young. The boys are of age and have already been involved in the conflict through the OoP and by Ron's having been with Harry all year.
> 
> Given what was going on at Hogwarts, Ginny has been involved too, but I'm not sure Molly really  knows that. But, at any rate, the baby of the family is always the baby. It takes a little longer to let them go.
>
Carol notes:
Absolutely, Ginny's being the youngest and not yet of age has something to do with it. But Molly's line, "Not my daughter, you b----!" does suggest--not that Ginny is less gifted or powerful than her brothers as a Witch rather than a Wizard (after all, look whom Molly is fighting)--but that there's something special to Molly about her only daughter. Ron is right, I think, that Molly (though she loves him dearly) was disappointed that he wasn't born a girl and tried again, one last time, to have a daughter with Ginny, at which point she stopped having children. So Ginny, as the youngest and the only girl, is doubly precious. But, also, setting aside JKR's glaring allusion to a certain film, Molly means, "You've killed my son Fred. You're not going to take my daughter, too." Or that's how I read it.

I think, though, that any of Molly's sons would have been humiliated if she'd stepped in to take over their battle because it would insult their competence, their maturity, and their masculinity. With Ginny, a fellow female and a "child," her (perceived) interference won't be resented as much, especially since Ginny herself could never have killed Bellatrix. And once Ginny has children of her own, any lingering resentment of her mother's taking over her battle will disappear as her own mother instinct kicks in.

Carol, just speaking from her own experience with teenage boys and girls