But it's okay when luther does:

Christ, our Savior, was the real and natural fruit of Mary's virginal womb . . . This was without the cooperation of a man, and she remained a virgin after that.

{Luther's Works, eds. Jaroslav Pelikan (vols. 1-30) & Helmut T. Lehmann (vols. 31-55), St. Louis: Concordia Pub. House (vols. 1-30); Philadelphia: Fortress Press (vols. 31-55), 1955, v.22:23 / Sermons on John, chaps. 1-4 (1539)}

Christ . . . was the only Son of Mary, and the Virgin Mary bore no children besides Him . . . I am inclined to agree with those who declare that 'brothers' really mean 'cousins' here, for Holy Writ and the Jews always call cousins brothers.

{Pelikan, ibid., v.22:214-15 / Sermons on John, chaps. 1-4 (1539)}

A new lie about me is being circulated. I am supposed to have preached and written that Mary, the mother of God, was not a virgin either before or after the birth of Christ . . .

{Pelikan, ibid.,v.45:199 / That Jesus Christ was Born a Jew (1523)}

Scripture does not say or indicate that she later lost her virginity . . .

When Matthew [1:25] says that Joseph did not know Mary carnally until she had brought forth her son, it does not follow that he knew her subsequently; on the contrary, it means that he never did know her . . . This babble . . . is without justification . . . he has neither noticed nor paid any attention to either Scripture or the common idiom.