Since the genitive plural all has the same article in the masc, fem, neut, in the 2, 1, 2 declensions is:

twn twn twn

and the case ending form genitive plural is wn for all words, how can I ever tell whether the word is masc, fem, or neut? With all the others I can use the article where the inflected ending is the same (like the gen sg. and the acc. pl.)

I hope that made sense. Thank you. (probably obvious, but w is omega).