asexualize vs sterilize

asexualize

verb
  • To render asexual. 

sterilize

verb
  • To make unable to produce; to make unprofitable. 

  • To deprive of the ability to procreate. 

  • To redact (a document), removing classified or sensitive material. 

  • To kill, deactivate (denature), or destroy (break apart) all living, viable microorganisms and spores on a surface, in a fluid, or contained in a compound, such as culture media or a medical product. 

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