Is there anything strange or ironic about Antigone being represented as a mother?

Antigone was not married and had no children. She is engaged to be married to Creon's son, Haemon, but because she is sentenced to death and ends up killing herself, Creon has taken away her chance to be a mother. When she is first presented to Creon and the guard describes her in terms of a mother bird wailing because its nest was empty, the description has some irony. The better picture would have been a fellow nestling bird crying when its brother falls to earth and dies, or something similar, because she was crying for her brother, not for her children. However, there is a sense in which Antigone repeats the shame and agony of her own mother in this play, and she refers to it herself several times. She feels she is cursed by the twisted relationship of her parents--her mother married her own son, and Antigone and her siblings were the products of that union. So Antigone's anguish echoes the anguish of her mother. Later, Antigone states that if she had been a mother and this was her son who was unburied rather than her brother, she would not have risked her life this way because she would be able to have another child. But since her parents are both dead, there is no way she can ever have another brother to replace Polyneices, so her sacrifice was appropriate. So it is strange and ironic to compare Antigone to a mother bird, but it helps carry through the idea of the family curse that Antigone's mother brought on her.