The Collaborative International Dictionary of English v.0.48:

Xenogenesis \Xen`o*gen"e*sis\, n. [Gr. xe`nos a stranger + E.
   genesis.] (Biol.)
   (a) Same as Heterogenesis.
   (b) The fancied production of an organism of one kind by an
       organism of another. --Huxley.
       [1913 Webster]

WordNet (r) 3.0 (2006):

xenogenesis
    n 1: the alternation of two or more different forms in the life
         cycle of a plant or animal [syn: alternation of
         generations, heterogenesis, xenogenesis]