gender identity vs procreation

gender identity

noun
  • A person's internal sense of self as belonging to a particular gender or genders, or to no gender. 

procreation

noun
  • The sexual activity of conceiving and bearing biological offspring 

  • The process by which an organism produces others of its biological kind 

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