diff --git a/ext/gtk2/rbgtkcontainer.c ext/gtk2/rbgtkcontainer.c
--- a/ext/gtk2/rbgtkcontainer.c
+++ ext/gtk2/rbgtkcontainer.c
@@ -496,6 +496,114 @@ static VALUE proc_mod_eval;
 static GQuark q_ruby_setter;
 static GQuark q_ruby_getter;
 
+struct param_setup_arg {
+    GObjectClass* gclass;
+    GParameter* params;
+    guint param_size;
+    VALUE params_hash;
+    guint index;
+};
+
+static VALUE
+_params_setup(VALUE arg,
+              VALUE rb_param_setup_arg,
+              G_GNUC_UNUSED int argc,
+              G_GNUC_UNUSED const VALUE *argv,
+              G_GNUC_UNUSED VALUE block)
+{
+    struct param_setup_arg *param_setup_arg =
+        (struct param_setup_arg *)rb_param_setup_arg;
+    guint index;
+    VALUE name, val;
+    GParamSpec* pspec;
+
+    index = param_setup_arg->index;
+    if (index >= param_setup_arg->param_size)
+       rb_raise(rb_eArgError, "too many parameters");
+
+    name = rb_ary_entry(arg, 0);
+    val  = rb_ary_entry(arg, 1);
+
+    if (SYMBOL_P(name))
+        param_setup_arg->params[index].name = rb_id2name(SYM2ID(name));
+    else
+        param_setup_arg->params[index].name = StringValuePtr(name);
+
+    pspec = g_object_class_find_property(
+        param_setup_arg->gclass,
+        param_setup_arg->params[index].name);
+    if (!pspec)
+        rb_raise(rb_eArgError, "No such property: %s",
+                 param_setup_arg->params[index].name);
+
+    g_value_init(&(param_setup_arg->params[index].value),
+                 G_PARAM_SPEC_VALUE_TYPE(pspec));
+    rbgobj_rvalue_to_gvalue(val, &(param_setup_arg->params[index].value));
+
+    param_setup_arg->index++;
+
+    return Qnil;
+}
+
+static VALUE
+gobj_new_body(VALUE rb_arg)
+{
+    struct param_setup_arg *arg = (struct param_setup_arg *)rb_arg;
+    ID id_each;
+    CONST_ID(id_each, "each");
+    rb_block_call(arg->params_hash, id_each, 0, NULL, _params_setup, (VALUE)arg);
+    return (VALUE)g_object_newv(G_TYPE_FROM_CLASS(arg->gclass),
+                                arg->param_size, arg->params);
+}
+
+static VALUE
+gobj_new_ensure(VALUE rb_arg)
+{
+    struct param_setup_arg *arg = (struct param_setup_arg *)rb_arg;
+    guint i;
+    g_type_class_unref(arg->gclass);
+    for (i = 0; i < arg->param_size; i++) {
+        if (G_IS_VALUE(&arg->params[i].value))
+            g_value_unset(&arg->params[i].value);
+    }
+    return Qnil;
+}
+
+static GObject*
+rbgobj_gobject_new_glib_425(GType gtype, VALUE params_hash)
+{
+    GObject* result;
+
+    if (!g_type_is_a(gtype, G_TYPE_OBJECT))
+        rb_raise(rb_eArgError,
+                 "type \"%s\" is not descendant of GObject",
+                 g_type_name(gtype));
+
+    if (NIL_P(params_hash)) {
+        result = g_object_newv(gtype, 0, NULL);
+    } else {
+        guint param_size;
+        struct param_setup_arg arg;
+
+        param_size = NUM2UINT(rb_funcall(params_hash, rb_intern("length"), 0));
+
+        arg.param_size = param_size;
+        arg.gclass = G_OBJECT_CLASS(g_type_class_ref(gtype));
+        arg.params = ALLOCA_N(GParameter, param_size);
+        memset(arg.params, 0, sizeof(GParameter) * param_size);
+        arg.params_hash = params_hash;
+        arg.index = 0;
+
+        result = (GObject*)rb_ensure(&gobj_new_body, (VALUE)&arg,
+                                     &gobj_new_ensure, (VALUE)&arg);
+    }
+
+    if (!result)
+        rb_raise(rb_eRuntimeError, "g_object_newv failed");
+
+    return result;
+}
+
 static VALUE
 cont_initialize(int argc, VALUE *argv, VALUE self)
 {
@@ -507,7 +615,7 @@ cont_initialize(int argc, VALUE *argv, VALUE self)
     if (!NIL_P(params_hash))
         Check_Type(params_hash, T_HASH);
 
-    gobj = rbgobj_gobject_new(RVAL2GTYPE(self), params_hash);
+    gobj = rbgobj_gobject_new_glib_425(RVAL2GTYPE(self), params_hash);
 
     RBGTK_INITIALIZE(self, gobj);
     return Qnil;
diff --git a/ext/gtk2/rbgtkobject.c ext/gtk2/rbgtkobject.c
--- a/ext/gtk2/rbgtkobject.c
+++ ext/gtk2/rbgtkobject.c
@@ -51,8 +51,9 @@ rg_s_type_register(int argc, VALUE *argv, VALUE klass)
     {
         VALUE initialize_module;
         initialize_module = rb_define_module_under(klass, "WidgetHook");
-        rbg_define_method(initialize_module,
-                          "initialize", rg_initialize, -1);
+#undef RG_TARGET_NAMESPACE
+#define RG_TARGET_NAMESPACE initialize_module
+        RG_DEF_METHOD(initialize, -1);
         rb_include_module(klass, initialize_module);
     }