Harry's right about the role of women in the medical department or as vivandiers. I don't think those taking exception to his statements have provided much beyond a list of names. It would help immeasurably if they could also provide some reputable original source citations.
As an example, we have this from "General Orders of the War Department" (available and searchable on Google Books):
"War Dep't, Adjutant General's Office
Washington, June 9, 1861
"Women nurses will not reside in the camps, nor accompany regiments on the march; but those who apply for service, and are highly accredited, having certificates from two Physicians, and two Clergymen of standing; and will forward the same to Miss D. L. Dix, at Washington, will receive a certificate in return accrediting them for service in any Military Hospital in the United States where such services are required.
L. Thomas, Adjutant General"
Further reading in the Surgeon's Manual and Steward's Manual makes it even clearer that the "any Military Hospital" referred to a general hospital in the rear. From a general order of the AOP written by Letterman, hospitals in time of battle consisted of field dressing stations managed by a small number of the regiment's medical personnel with the majority of such personnel consolidated at divisional hospitals. There was plenty of work for women and civilian employees of the Hospital Corps in Washington City, Philadelphia and elsewhere.
So, apart from an individual impression of Mary Tepe at Fredericksburg or Clara Barton at Antietam, there really is no role for a woman on the battlefield unless she's portraying a man, and even the documentation for Tepe and Barton is, as I recall, pretty weak.
If someone has a contemporary original source that would indicate otherwise, I would love to see it. I have not been able to find anything of the sort in the ORs or the books and periodicals on the Cornell MOA site.
M. A. Schaffner
Midstream Regressive Complainer