asexualization
noun
asex·u·al·i·za·tion
variants:
also British asexualisation \ (ˈ)ā-ˌseksh-(ə-)wə-lə-ˈzā-shən, -ˌsek-shə-lə- 
\
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Medical Definition of asexualization
: the process of destroying the capacity for reproduction especially by surgical means : sterilization, castration