AARGH!
First step should be to review the edit history for "Doe-200" to see if the addition of parents was logged.
If the addition of parents isn't logged, next step is to contact the profile manager for Doe-200. They may have the information about parents -- and they are likely unaware that parents are no longer selected by default when profiles are merged.
If the profile manager can't help you, then you can try looking at the profile manager's contributions history from around the time Doe-200 was created -- maybe the creation of the parents' profiles (where the connection to the child is likely to be logged) can be detected in the contributions history.
Or you could look at the surname genealogy page for "Doe" -- sort the surname list by birth date and look for people in the right time period and with the right geography to possibly be this person's parents.