Actually, izobcenec, 'allogeneic' is the correct spelling.
From m-w.com:
Main Entry: al·lo·ge·ne·ic 
Pronunciation: "a-lO-j&-'nE-ik
Variant(s): also al·lo·gen·ic /-'je-nik/
Function: adjective
Etymology: all- + -geneic (as in syngeneic)
Date: 1961
: involving, derived from, or being individuals of the same species that are sufficiently unlike genetically to interact antigenically
Pronunciation: "a-lO-j&-'nE-ik
Variant(s): also al·lo·gen·ic
/-'je-nik/Function: adjective
Etymology: all- + -geneic (as in syngeneic)
Date: 1961
: involving, derived from, or being individuals of the same species that are sufficiently unlike genetically to interact antigenically