A wee Irish song

This afternoon I heard a radio interview with Irish singer Kathy Ryan, who is performing with the Detroit Symphony Orchestra this weekend (I'm not going). At the end of the interview the host played a song from one of her recordings. In the song a man tells his grown daughter she can't marry any of the young men of the village because he is the father of all of them, so they are all kin. She goes to her mother, who tells her, marry any man you like. The one who told you this is not your father.