well, there is also the conversation between Charlie and the nurse in the abortion clinic.
I would count the conversations that Kitten had the other women as well, since she clearly identified as being female
This movie passed 3 of 3 tests. It was entered by silverfish on 2015-01-04 00:41:00.
The mother punishes him, during which she says he will be a disgrace to them, and Caroline tells her mother to punish him harder. I think it just counts as talking to each other, although they talk to Patrick too. The conversation is obviously about a man (or boy, in this case).
The other conversation, around 18 minutes in Caroline says "Jesus, Mammy I'm exhausted", who replies "At least you have a job, which is more than that wastrel yonder is ever likely to have", then she starting talking to Patrick, so there only two lines, between the two female characters, one of which is in part about a man.
The mother is just "Ma Braden", which I think should count as a named character, she isn't the typical "Woman in Shop" unnamed character.
They are definitely at least two significant female characters. Charlie is a significant character and Eily Bergin is Patrick's birth mother who he is looking for, although she only appears in a few scenes.