First of all Haller is not so common a name in Germany, there are only about 3500 entries in dastelefonbuch - in a population of 6m. However I do not think that would be much use even if you decided to go that way. As for DNA - I do not really know much about it but from what I understand it is not much use for personal search - might show you have a Jewish/African/Scandinavian links but so do millions of others. It would not be something I would give serious consideration to at the moment. What might be more useful, as Frankfurt seems to be proving helpful, would be to ask if there is any chance they could look to see if there are any other birth records for Berta - i.e. a child about two years older? Also could they find out if Berta had brothers and sisters - you have the parents' names? If she did, someone there might know what happened. What about the people who adopted her, are there any clues in the adoption papers? Do you know why she suddenly went to Worms? Any addresses you have might help. There is something in Germany called Meldepflicht - i.e. you have to register where you are living. Was her sister's name in Frankfurt Haller or something else - and how did she know it was Berta's sister? If the "brother" was living in the house along with his aunt there would be a record of him living at that address, presumably under the name of Haller if she had never married, but if he really was there under that name it might be possible to get a birth certificate for him. Don't know if any of this is useful but when you are faced with a problem a bit of later thinking does not hurt. Good luck anyway.