Friedrich Georg (Fedor Pavlovich) von Adelung - Friedrich Adelung another wife?

I have two documents that I will add to my tree that show Friedrich G. Adelung was possible the father to 3 other children. I been searching all over and I can't find another Friedrich G. Adelung. The mother of the 3 children was Sophie Adelung born in 1798. I know that is a 30 year age difference and he was in Russia at the time of birth of the other 3 children. I guess the only way really to prove anything is DNA. I have my DNA on a few sites including Ancestry. Let me know if anyone that is related to Friedrich has taking a DNA test. Thank you, Jason Adelung

http://auswanderer-thueringen.de/genealogy/getperson.php?personID=I...