gender identity vs sexual intercourse

gender identity

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

sexual intercourse

noun
  • Sexual interaction, usually involving vaginal and/or anal and/or oral penetration, between at least two organisms. 

  • Coitus or genital-genital sexual contact. 

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