When the Sole Survivor first talks to Dr. Forsythe, he will ask that they give a blood sample for his research due to the fact that the vault dwellers have been "genetically isolated" while living in the vault. The Sole Survivor can refuse or accept to donate, or sell blood. Giving blood is a hidden requirement to start the quest Hole in the Wall.
In a random encounter, the Sole Survivor may find a dead settler with a dead dog. The settler carries a note from Dr. Forsythe asking for a list of medical supplies, and instructing the carrier to use the intercom when they arrive.