I see to recall an implication in the corpus somewhere that some of Thorin's companions in the Hobbit were female, unbeknownst to non-Dwarves...
Not sure which ones that would be since there were three pairs of brothers (Fili and Kili, Oin and Gloin, and Balin and Dwalin) And a trio of male cousins (Bifur, Bofur, and Bombur), so just leaves Ori, Nori, and Dori, who I can't remember if they were directly related to each other or just similarly named. And I am pretty sure Ori is referred to as male, as he went on the failed attempt to retake Moria. So that leaves just Dori and Nori and I can't remember if there are any specific references to them as "he".
And yes, if we think of "The Hobbit" being written from Bilbo's point of view, they would all seem male because they all have beards and are not referred to in any other way by the other dwarves or Gandalf, but I cannot remember if there are non-story references from the appendices or another book where Tolkien calls them all male.
Here is a video that includes the film scene from LotR mentioned earlier. It also includes footage from the film version of The Hobbit showing beardless Dwarf women:
Edit: Okay, there are these two quotes from Tolkien's writing:
They are in voice and appearance, and in garb [clothes] if they must go on a journey, so like to the dwarf-men that the eyes and ears of other peoples cannot tell them apart.
...no Man nor Elf has ever seen a beardless Dwarf - unless he were shaven in mockery, and would then be more like to die of shame... For the Naugrim have beards from the beginning of their lives, male and female alike...
I need to track down the exact book and page for that second one to verify it, as that one is pretty clear.
Edit 2: found it.
The War of the Jewels, HoME Vol 11, Part 2, Ch 13,
Concerning the Dwarves
Meaning it is from manuscripts not published til after JRR Tolkien's death. Now I can see the confusion about this topic, since while it did get into a published work, it was not in something he had published while still alive.