[William Cloud Hicklin]

Even there, though, Tolkien cites Galadriel *and* Celeborn as co-rulers; he couldn't bring himself to make even the greatest (tie) of all the Eldar a sole ruler in her own right- and this despite the fact that Galadriel was by far superior to he husband in both native power and royal lineage. No Elf-king seems to share rule with his consort! (At least, not if she isn't a demi-goddess).

Here naturally Tolkien is simply being a man of his time, and a product of long European and English tradition. Of England's first three ruling queens, two had to share the crown with their husbands in dual monarchies (Philip and Mary, William and Mary), and the third (Elizabeth) ducked marriage so to avoid that fate. The three since have been carefully paired with "prince consorts;" a King can have a Queen, but not the reverse. In much of the Continent it's worse: Salic law applied and no female could inherit or even transmit inheritance (that's why Victoria was never Queen of Hanover though her uncles and grandfather had been Kings).

As to the 'physical strength' business- in olden days there was a certain logic to that, so long as kings were expected to go out personally and hack at other big men with meat cleavers. It's notable that while Numenor moved from strict male primogeniture to either male-preference or gender-neutral primogeniture (depending on the version of the amended succession law one accepts), neither of the kingdoms in exile ever had a ruling Queen; and this difference can I think be explained by the fact that Numenor was mostly at peace and was never threatened at home, whereas the tale of the North and South Kingdoms is one of constant war.

EDIT: In fact, Gondor passed the crown to a cadet line, and then allowed the Kingship to lapse entirely, rather than even consider a claim by or through a perfectly valid princess, Firiel. Plainly the revised Numenorean law did *not* apply in the South-kingdom.