baby of the family vs offspring

baby of the family

noun
  • An adult member of an immediate family who is treated by others in the family, especially the parents, as though they were a child. 

  • The youngest member of an immediate family. 

  • A member of an immediate family who behaves as, or is treated as though they were the youngest member of a family. 

offspring

noun
  • A person's daughter(s) and/or son(s); a person's children. 

  • All of a person's descendants, including further generations. 

  • An animal or plant's progeny or young. 

  • Anything produced; the result of an entity's efforts. 

  • A process launched by another process. 

How often have the words baby of the family and offspring occurred in a corpus of books? (source: Google Ngram Viewer )