diff --git a/include/extern.h b/include/extern.h
index 1cb0d673d..491b84367 100644
--- a/include/extern.h
+++ b/include/extern.h
@@ -1310,7 +1310,7 @@ E boolean FDECL(hideunder, (struct monst*));
 E void FDECL(hide_monst, (struct monst *));
 E void FDECL(mon_animal_list, (BOOLEAN_P));
 E int FDECL(select_newcham_form, (struct monst *));
-E void FDECL(mgender_from_permonts, (struct monst *, struct permonst *));
+E void FDECL(mgender_from_permonst, (struct monst *, struct permonst *));
 E int FDECL(newcham, (struct monst *,struct permonst *,BOOLEAN_P,BOOLEAN_P));
 E int FDECL(can_be_hatched, (int));
 E int FDECL(egg_type_from_parent, (int,BOOLEAN_P));