I would think that it is likely that we are looking for someone that may not have known she was/is a Doering by birth. The adoption was done at a time where I don't think they shared one bit of information ever.
It is possible the adoptive parents could have completely re-named their adopted child. Wow, where to go next? I am going to try and hone in on the "Oakley/ Brentwood" area. We have a Brentwood city/area near Santa Monica in Los Angeles County. I don't know if it was known as Brentwood back in the 1930's but that can be found out. Oakley has me stumped and I wonder if the person you spoke with meant Oakland which would be near or in Alameda. Back in the 1930's there was a lot of fruit packing places and many were located near farms as well as railroad stations. There are places here today in Los Angeles (city) that are home to fruit wholesalers that were likely there back in the 1930's. Since the 1940 Census is not released yet, I'm thinking that I want to locate Mr. Truesdale as well as Betty's family so we can get a better fix on where this all happened. I will also do a search for Native Sons & Daughters Adoption agency. I can also search the Calif. birth indexing for 1932. I am considering that the child could have been born in July or even June before being adopted in August. Did your informant know if the baby went immediately to the new family? I know there were times when the babies stayed in orphanages and cared for as an example of St. Anne's by nuns until they went to new homes. I use St. Anne's Home for Unwed Mothers (was located in the city of Los Angeles as an example as the "unwed mom" went home after normal amount of time following birth and the baby remained in care of the "sisters" as the adoption process was completed. I had a friend who stayed at St. Anne's back in the 1970's and they did not encourage a lot of contact with the newborn. However they seemed to want children to stay with their natural family when it could be worked out. I know that my friend named her child but did not know if the name would stay the same but she was given photos of her baby after it was adopted. I don't know what they did in those days. As it is today things have changed greatly since the 1970's.
Do you know if Mr. Truesdale was arrested for getting this girl pregnant? This would have been a shameful event for Betty's family. This would have been a difficult time for the family so they could have moved or sent their daughter to live out of town until she gave birth to save face.
If it should turn out that the baby was renamed and we can't locate her all is not lost. It could be possible that someone could be searching from the other side working toward you. So, we should include as much as we can in the way of information in our posts to leave a trail for an opportunity for that person searching for a birth mother or father information. I will see what I can find on Native Sons & Native Daughters Adoption Agency, in hopes of a clue from their location. Please post any other details even if they seem minor as they might be helpful. An interesting thing I notice here is that "Betty" used a common or customary naming thing in the naming of her child which "re-uses" family names in a prior generation. This could be a clue to her parent's first names.