baby boy vs little boy

baby boy

noun
  • A very young male human being, from birth to a couple of years old. 

  • A term of endearment for a man. 

  • A man who is immature or infantile. 

little boy

noun
  • A male child, especially one younger than ten years of age. 

  • A small saveloy often consumed with tomato sauce at parties, also known as a cocktail sausage or a cheerio. 

  • A male perceived to be weaker than or subservient to another; or a boy who is too young for their job. 

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