Svetabel is true. At these times, it was a good deal of gossip about Anna Ivanovna giving birth to the three Biron´s children. I never read nothing about Karl Ernst, but I read some comments about his older son Peter, later duke of Courland. But, in fact, when Benigna Gottlieb von Trotta und Treyden, Biron´s wife, was delivered from his son Peter in Mittau, both Anna Ivanovna and Ernst Johann were not in the city. Knowing he was father of a male son, Ernst Johann wrotte to Benigna a very tender letter.
Karl Ernst shared the fate of his parents, brother and sister Hedwig. All the family spent decades in a not fair exile, only the girl -Hedwig- ran away from exile and found a place in the court of empress Elizabeth, where she was married to a nobleman.