Generally, vowels are female and consonants are male.
Thus the thirty consonants beginning with ka (ཀྭ་) are all male,
But they are also divided into five sections:
ka (ཀ་), ca (ཅ་), ta (ཏ་), pa (པ་) and tsa (ཙ་) are male;
kha (ཁ་), cha (ཆ་), tha (ཐ་), pha (ཕ་) and tsha (ཚ་) are neuter;
ga (ག་), ja (ཇ་), da (ད་), ba (བ་), dza (ཛ་), wa (ཝ་), zha (ཞ་),
za (ཟ་), ‘a (འ་), ya (ཡ་), sha (ཤ་) and sa (ས་) are female;
nga (ང་), nya (ཉ་), na (ན་) and ma (མ་) are very female;
ra (ར་), la (ལ་), ha (ཧ་) and a (ཨ་) are extremely female.
a (ཨ་) is also called signless.