In game tooltip:
30% chance: to create a Medical Generator when creating a Shield Generator.
Tested 10 times creating a Medical Generator to see if wiki statement:
Specialization: Transporter Officer Creating a Medical Generator has a chance of also creating a Shield Generator, while creating a Shield Generator has a chance of creating a Medical Generator.
30% chance: to create a Shield Generator when creating a Medical Generator. 30% chance: to create a Medical Generator when creating a Shield Generator.
was true. No Shield Generator was created while doing 10 times (on 2 BOFFs) creating Shield Generator caused 4 on one and 2 on the other to create a Medical Generator.