It's "children" or possibly "child's", but never "childs".

Note: this affects several user visible strings.




gnome/gtk+/gtk> grep -w childs *.[ch] */*.[ch]
gtkcombobox.c:          GList *childs;
gtkcombobox.c:          childs = gtk_container_get_children (GTK_CONTAINER
(combo_box->priv->popup_widget));
gtkcombobox.c:                                      g_list_nth_data
(childs, combo_box->priv->active_item));
gtkcombobox.c:          g_list_free (childs);
gtkcombobox.c:          /* handle the childs */
gtkcombobox.c:  /* changing the popup window will unref the menu and the
childs */
gtknotebook.c:                                                            
P_("The string displayed on the childs tab label"),
gtknotebook.c:                                                            
P_("The string displayed in the childs menu entry"),
gtknotebook.c:                                                            
 P_("Whether to expand the childs tab or not"),
gtknotebook.c:                                                            
 P_("Wheather the childs tab should fill the allocated area or not"),
gtktreemodelfilter.c:  GtkTreeIter childs;
gtktreemodelfilter.c:      /* and update the childs */
gtktreemodelfilter.c:      if (gtk_tree_model_iter_children (c_model,
&childs, &real_c_iter))
gtktreemodelfilter.c:  if (gtk_tree_model_iter_children (c_model, &childs,
c_iter))
gtktreemodelfilter.c:  /* another iteration to update the references of
childs to parents. */
gtktreestore.c:      g_warning ("Given childs are not in the same level\n");
gtktreestore.c:          g_warning ("Given childs are not in the same
level\n");
gtktreestore.c:          g_warning ("Given childs are not in the same
level\n");
gtktreeview.c:      /* totally ignore our childs requisition */