Yeah, it never got revisited/explicitly mentioned, but between the description of the forest, and the way the ents describe what happens when they are alone for too long, its hard not to think the forest is full of entwives.

The only named tree being male could be that a single male went with/found/was born among the entwives and also 'went feral', or it could be a mistranslation (in world or IRL) or the gender used got changed over time as people forgot it was a female tree (as it has been far too long since I read any Tolkien books to remember who voiced the trees name - if it was Bombadil this point is obviously moot)