Hi, and thanks for taking the time to reply.
My interest in the Christina family is that they are part of my extended paternal family. As for the Christina family, I've gotten back to one set of John's maternal great grandparents.
Additionally, I have learned that one of John's brothers died in England, and that the son and daughter-in-law of another brother are living in Forest City, PA.
In answer to your question, here is what I have found. John and Sylvia Christina had at least one child, who also had at least one child. I am hesitant to discuss current individuals, but would be willing to discuss my research privately.
If you are interested in any sharing of family information (past and current), please contact me directly at firstname.lastname@example.org