The Collaborative International Dictionary of English v.0.48:

desexualize \desexualize\ v. i. & t.
   to direct one's libidinous urges into another direction.
   [WordNet 1.5]

   2. same as desex.

   Syn: sterilize, desex, unsex, fix, make infertile.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

desexualize
    v 1: direct one's libidinous urges into another direction [syn:
         desexualize, desexualise]
    2: make infertile; "in some countries, people with genetically
       transmissible disabilites are sterilized" [syn: sterilize,
       sterilise, desex, unsex, desexualize, desexualise,
       fix]