sentences:  The youngest queen regnant to give birth is Mary II, who gave birth to a stillborn child in 1678, prior to her accession, when she was just 16.The youngest mother to give birth to a monarch was Lady Margaret Beaufort, wife of Edmund Tudor, who was 13 years and almost 8 months when she gave birth to Henry VII in 1457.The oldest King to become a father was Edward I, who fathered his last child, Eleanor, in 1306, when he was 66, almost 67 years old.