[Numenorean]

Given the elegant and highly intelligent posts that have gone before me in this thread, please excuse my clumsy attempts at focussing on only one aspect of a vast topic. I agree entirely with your viewpoint here Saucey:

The Saucepan Man
Tolkien's tale concerns only one part of Middle-earth…. Who is to say that there was not a society of warrior women in the far south or the far east of Middle-earth who played no (or little) part in the events which he relays?

I am going to put Haleth and her people forward as a clear example of the existence of warrior Women within the Legendarium. As a female warrior ‘of great heart and strength’, Haleth was not an exception amongst her people, indeed for the Haladin it would seem that mixed gender warriors were in fact the traditional ‘norm’.

From Unfinished Tales – Part Four - The Drúedain:
Regarding the Folk of Haleth JRRT states –

“…many of their warriors were women” and “This custom was evidently ancient; for their chieftainess Haleth was a renowned Amazon with a picked bodyguard of women.”

With this mixed gender army, the Haladin – despite being only few in numbers – were significantly skilled enough in military matters for their reputation amongst the Eldar, the Edain and the Orcs of Beleriand to be as follows:

“…they were esteemed as loyal allies and redoubtable warriors…..and they excelled in forest warfare. Indeed for long even those Orcs specially trained for this dared not set foot near their borders”

Christopher Tolkien seems somewhat bemused in the footnotes to this chapter that ‘nothing is said in The Silmarillion about the Amazonian element in their society, other than that the Lady Haleth was a warrior.’

Mister Underhill
Éowyn is also described in at least two instances in the professor's notes as an "amazon". I don't know if that means anything about anything, or if it offers any insights.

Perhaps the Profs notes infer that Éowyn was not the solitary Amazonian warrior-type that she is sometimes thought to be, but in fact she was just a more high-profile example of an ancient tradition that stretches back across the history of the Atani, as glimpsed in the writings concerning the Folk of Haleth.

In ‘real world’ history I find interesting parallels – maybe JRRT did too – between Haladin and Celtic society, where women participated in both warfare and kingship. Indeed, among the ancient Celts, women rulers and warriors were so common that when a group of Brigantian (Brit Celts) captives were brought to Rome in the reign of Claudius they automatically assumed his wife, Agrippina the Younger, was the ruler and ignored the Emperor while making their obeisance to her. There is also Bodiecia and her renowned Iceni army, which was described by the Roman historian Tacitus as having "in their ranks more women than fighting men." A final example (among a myriad of historical references) comes from another Roman author, Ammianus Marcellinus, who describes Gaulish(Celtic) women as being even stronger than their husbands and fighting with their fists and kicks at the same time "like missiles from a catapult".

Lush
All of the bonding, camaraderie, and shared responsibility, in my opinion could have easily occured within a mixed-gender setting

I completely agree. As history clearly shows, women were (and are) more than a match for and often surpass men in combat, therefore the often heard arguments that ‘there could be no females in the Fellowship because they were unable to compete with men in military matters’ or ‘that it wouldn’t be realistic’ (etc) are, in my opinion, nonsense.