fathership vs motherhood

fathership

noun
  • The state of being a father; fatherhood; paternity. 

  • A title of respect addressed to a priest. 

motherhood

noun
  • The state of being a mother. 

  • Mothers, considered as a group. 

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