Solving this requires logical reasoning involving the rules of word ladders as well as family relationships. Some outside general knowledge is required. (Note: Though later added to OSPD 5th ed., "cert" was not a valid Scrabble word when this quiz was created in 2013.)
Some rungs contain names of family members; the rest contain ordinary words. Every name is a well-known personal name, and every word is a valid Scrabble word (OSPD 4th ed.). Standard word ladder rules apply, including the fact that bungs (consecutive changes in the same position, such as FILL-KILL-BILL) are forbidden. "Adjacent" means that two rungs are immediately above or below each other.