diff --git a/google/cloud/securitycenter_v1/services/security_center/transports/base.py b/google/cloud/securitycenter_v1/services/security_center/transports/base.py
index 1eb5b65a..8b8719b2 100644
--- a/google/cloud/securitycenter_v1/services/security_center/transports/base.py
+++ b/google/cloud/securitycenter_v1/services/security_center/transports/base.py
@@ -116,7 +116,7 @@ def __init__(
         scopes_kwargs = self._get_scopes_kwargs(self._host, scopes)
 
         # Save the scopes.
-        self._scopes = scopes or self.AUTH_SCOPES
+        self._scopes = scopes
 
         # If no credentials are provided, then determine the appropriate
         # defaults.
diff --git a/google/cloud/securitycenter_v1/services/security_center/transports/grpc.py b/google/cloud/securitycenter_v1/services/security_center/transports/grpc.py
index 523ad20d..409d20b7 100644
--- a/google/cloud/securitycenter_v1/services/security_center/transports/grpc.py
+++ b/google/cloud/securitycenter_v1/services/security_center/transports/grpc.py
@@ -75,6 +75,7 @@ def __init__(
         client_cert_source_for_mtls: Callable[[], Tuple[bytes, bytes]] = None,
         quota_project_id: Optional[str] = None,
         client_info: gapic_v1.client_info.ClientInfo = DEFAULT_CLIENT_INFO,
+        always_use_jwt_access: Optional[bool] = False,
     ) -> None:
         """Instantiate the transport.
 
@@ -115,6 +116,8 @@ def __init__(
                 API requests. If ``None``, then default info will be used.
                 Generally, you only need to set this if you're developing
                 your own client library.
+            always_use_jwt_access (Optional[bool]): Whether self signed JWT should
+                be used for service account credentials.
 
         Raises:
           google.auth.exceptions.MutualTLSChannelError: If mutual TLS transport
@@ -168,7 +171,7 @@ def __init__(
             scopes=scopes,
             quota_project_id=quota_project_id,
             client_info=client_info,
-            always_use_jwt_access=True,
+            always_use_jwt_access=always_use_jwt_access,
         )
 
         if not self._grpc_channel:
diff --git a/google/cloud/securitycenter_v1/services/security_center/transports/grpc_asyncio.py b/google/cloud/securitycenter_v1/services/security_center/transports/grpc_asyncio.py
index 4dcdf582..7c83eee0 100644
--- a/google/cloud/securitycenter_v1/services/security_center/transports/grpc_asyncio.py
+++ b/google/cloud/securitycenter_v1/services/security_center/transports/grpc_asyncio.py
@@ -121,6 +121,7 @@ def __init__(
         client_cert_source_for_mtls: Callable[[], Tuple[bytes, bytes]] = None,
         quota_project_id=None,
         client_info: gapic_v1.client_info.ClientInfo = DEFAULT_CLIENT_INFO,
+        always_use_jwt_access: Optional[bool] = False,
     ) -> None:
         """Instantiate the transport.
 
@@ -162,6 +163,8 @@ def __init__(
                 API requests. If ``None``, then default info will be used.
                 Generally, you only need to set this if you're developing
                 your own client library.
+            always_use_jwt_access (Optional[bool]): Whether self signed JWT should
+                be used for service account credentials.
 
         Raises:
             google.auth.exceptions.MutualTlsChannelError: If mutual TLS transport
@@ -214,7 +217,7 @@ def __init__(
             scopes=scopes,
             quota_project_id=quota_project_id,
             client_info=client_info,
-            always_use_jwt_access=True,
+            always_use_jwt_access=always_use_jwt_access,
         )
 
         if not self._grpc_channel:
diff --git a/google/cloud/securitycenter_v1beta1/services/security_center/transports/base.py b/google/cloud/securitycenter_v1beta1/services/security_center/transports/base.py
index dad8d297..580a82d6 100644
--- a/google/cloud/securitycenter_v1beta1/services/security_center/transports/base.py
+++ b/google/cloud/securitycenter_v1beta1/services/security_center/transports/base.py
@@ -113,7 +113,7 @@ def __init__(
         scopes_kwargs = self._get_scopes_kwargs(self._host, scopes)
 
         # Save the scopes.
-        self._scopes = scopes or self.AUTH_SCOPES
+        self._scopes = scopes
 
         # If no credentials are provided, then determine the appropriate
         # defaults.
diff --git a/google/cloud/securitycenter_v1beta1/services/security_center/transports/grpc.py b/google/cloud/securitycenter_v1beta1/services/security_center/transports/grpc.py
index 1a4e4886..76795564 100644
--- a/google/cloud/securitycenter_v1beta1/services/security_center/transports/grpc.py
+++ b/google/cloud/securitycenter_v1beta1/services/security_center/transports/grpc.py
@@ -72,6 +72,7 @@ def __init__(
         client_cert_source_for_mtls: Callable[[], Tuple[bytes, bytes]] = None,
         quota_project_id: Optional[str] = None,
         client_info: gapic_v1.client_info.ClientInfo = DEFAULT_CLIENT_INFO,
+        always_use_jwt_access: Optional[bool] = False,
     ) -> None:
         """Instantiate the transport.
 
@@ -112,6 +113,8 @@ def __init__(
                 API requests. If ``None``, then default info will be used.
                 Generally, you only need to set this if you're developing
                 your own client library.
+            always_use_jwt_access (Optional[bool]): Whether self signed JWT should
+                be used for service account credentials.
 
         Raises:
           google.auth.exceptions.MutualTLSChannelError: If mutual TLS transport
@@ -165,7 +168,7 @@ def __init__(
             scopes=scopes,
             quota_project_id=quota_project_id,
             client_info=client_info,
-            always_use_jwt_access=True,
+            always_use_jwt_access=always_use_jwt_access,
         )
 
         if not self._grpc_channel:
diff --git a/google/cloud/securitycenter_v1beta1/services/security_center/transports/grpc_asyncio.py b/google/cloud/securitycenter_v1beta1/services/security_center/transports/grpc_asyncio.py
index 34e2ee8f..345bbc25 100644
--- a/google/cloud/securitycenter_v1beta1/services/security_center/transports/grpc_asyncio.py
+++ b/google/cloud/securitycenter_v1beta1/services/security_center/transports/grpc_asyncio.py
@@ -118,6 +118,7 @@ def __init__(
         client_cert_source_for_mtls: Callable[[], Tuple[bytes, bytes]] = None,
         quota_project_id=None,
         client_info: gapic_v1.client_info.ClientInfo = DEFAULT_CLIENT_INFO,
+        always_use_jwt_access: Optional[bool] = False,
     ) -> None:
         """Instantiate the transport.
 
@@ -159,6 +160,8 @@ def __init__(
                 API requests. If ``None``, then default info will be used.
                 Generally, you only need to set this if you're developing
                 your own client library.
+            always_use_jwt_access (Optional[bool]): Whether self signed JWT should
+                be used for service account credentials.
 
         Raises:
             google.auth.exceptions.MutualTlsChannelError: If mutual TLS transport
@@ -211,7 +214,7 @@ def __init__(
             scopes=scopes,
             quota_project_id=quota_project_id,
             client_info=client_info,
-            always_use_jwt_access=True,
+            always_use_jwt_access=always_use_jwt_access,
         )
 
         if not self._grpc_channel:
diff --git a/google/cloud/securitycenter_v1p1beta1/services/security_center/transports/base.py b/google/cloud/securitycenter_v1p1beta1/services/security_center/transports/base.py
index 05748267..784492f2 100644
--- a/google/cloud/securitycenter_v1p1beta1/services/security_center/transports/base.py
+++ b/google/cloud/securitycenter_v1p1beta1/services/security_center/transports/base.py
@@ -118,7 +118,7 @@ def __init__(
         scopes_kwargs = self._get_scopes_kwargs(self._host, scopes)
 
         # Save the scopes.
-        self._scopes = scopes or self.AUTH_SCOPES
+        self._scopes = scopes
 
         # If no credentials are provided, then determine the appropriate
         # defaults.
diff --git a/google/cloud/securitycenter_v1p1beta1/services/security_center/transports/grpc.py b/google/cloud/securitycenter_v1p1beta1/services/security_center/transports/grpc.py
index 57e8287f..a5c0867f 100644
--- a/google/cloud/securitycenter_v1p1beta1/services/security_center/transports/grpc.py
+++ b/google/cloud/securitycenter_v1p1beta1/services/security_center/transports/grpc.py
@@ -77,6 +77,7 @@ def __init__(
         client_cert_source_for_mtls: Callable[[], Tuple[bytes, bytes]] = None,
         quota_project_id: Optional[str] = None,
         client_info: gapic_v1.client_info.ClientInfo = DEFAULT_CLIENT_INFO,
+        always_use_jwt_access: Optional[bool] = False,
     ) -> None:
         """Instantiate the transport.
 
@@ -117,6 +118,8 @@ def __init__(
                 API requests. If ``None``, then default info will be used.
                 Generally, you only need to set this if you're developing
                 your own client library.
+            always_use_jwt_access (Optional[bool]): Whether self signed JWT should
+                be used for service account credentials.
 
         Raises:
           google.auth.exceptions.MutualTLSChannelError: If mutual TLS transport
@@ -170,7 +173,7 @@ def __init__(
             scopes=scopes,
             quota_project_id=quota_project_id,
             client_info=client_info,
-            always_use_jwt_access=True,
+            always_use_jwt_access=always_use_jwt_access,
         )
 
         if not self._grpc_channel:
diff --git a/google/cloud/securitycenter_v1p1beta1/services/security_center/transports/grpc_asyncio.py b/google/cloud/securitycenter_v1p1beta1/services/security_center/transports/grpc_asyncio.py
index 606fb3a7..0fc54f7a 100644
--- a/google/cloud/securitycenter_v1p1beta1/services/security_center/transports/grpc_asyncio.py
+++ b/google/cloud/securitycenter_v1p1beta1/services/security_center/transports/grpc_asyncio.py
@@ -123,6 +123,7 @@ def __init__(
         client_cert_source_for_mtls: Callable[[], Tuple[bytes, bytes]] = None,
         quota_project_id=None,
         client_info: gapic_v1.client_info.ClientInfo = DEFAULT_CLIENT_INFO,
+        always_use_jwt_access: Optional[bool] = False,
     ) -> None:
         """Instantiate the transport.
 
@@ -164,6 +165,8 @@ def __init__(
                 API requests. If ``None``, then default info will be used.
                 Generally, you only need to set this if you're developing
                 your own client library.
+            always_use_jwt_access (Optional[bool]): Whether self signed JWT should
+                be used for service account credentials.
 
         Raises:
             google.auth.exceptions.MutualTlsChannelError: If mutual TLS transport
@@ -216,7 +219,7 @@ def __init__(
             scopes=scopes,
             quota_project_id=quota_project_id,
             client_info=client_info,
-            always_use_jwt_access=True,
+            always_use_jwt_access=always_use_jwt_access,
         )
 
         if not self._grpc_channel:
diff --git a/tests/unit/gapic/securitycenter_v1/test_security_center.py b/tests/unit/gapic/securitycenter_v1/test_security_center.py
index 44b79ccf..7fac76c8 100644
--- a/tests/unit/gapic/securitycenter_v1/test_security_center.py
+++ b/tests/unit/gapic/securitycenter_v1/test_security_center.py
@@ -156,7 +156,25 @@ def test_security_center_client_service_account_always_use_jwt(client_class):
     ) as use_jwt:
         creds = service_account.Credentials(None, None, None)
         client = client_class(credentials=creds)
-        use_jwt.assert_called_with(True)
+        use_jwt.assert_not_called()
+
+
+@pytest.mark.parametrize(
+    "transport_class,transport_name",
+    [
+        (transports.SecurityCenterGrpcTransport, "grpc"),
+        (transports.SecurityCenterGrpcAsyncIOTransport, "grpc_asyncio"),
+    ],
+)
+def test_security_center_client_service_account_always_use_jwt_true(
+    transport_class, transport_name
+):
+    with mock.patch.object(
+        service_account.Credentials, "with_always_use_jwt_access", create=True
+    ) as use_jwt:
+        creds = service_account.Credentials(None, None, None)
+        transport = transport_class(credentials=creds, always_use_jwt_access=True)
+        use_jwt.assert_called_once_with(True)
 
 
 @pytest.mark.parametrize(
@@ -6876,7 +6894,7 @@ def test_security_center_grpc_transport_client_cert_source_for_mtls(transport_cl
             "squid.clam.whelk:443",
             credentials=cred,
             credentials_file=None,
-            scopes=("https://www.googleapis.com/auth/cloud-platform",),
+            scopes=None,
             ssl_credentials=mock_ssl_channel_creds,
             quota_project_id=None,
             options=[
@@ -6985,7 +7003,7 @@ def test_security_center_transport_channel_mtls_with_client_cert_source(
                 "mtls.squid.clam.whelk:443",
                 credentials=cred,
                 credentials_file=None,
-                scopes=("https://www.googleapis.com/auth/cloud-platform",),
+                scopes=None,
                 ssl_credentials=mock_ssl_cred,
                 quota_project_id=None,
                 options=[
@@ -7032,7 +7050,7 @@ def test_security_center_transport_channel_mtls_with_adc(transport_class):
                 "mtls.squid.clam.whelk:443",
                 credentials=mock_cred,
                 credentials_file=None,
-                scopes=("https://www.googleapis.com/auth/cloud-platform",),
+                scopes=None,
                 ssl_credentials=mock_ssl_cred,
                 quota_project_id=None,
                 options=[
diff --git a/tests/unit/gapic/securitycenter_v1beta1/test_security_center.py b/tests/unit/gapic/securitycenter_v1beta1/test_security_center.py
index 86d2bb14..7cb1fe75 100644
--- a/tests/unit/gapic/securitycenter_v1beta1/test_security_center.py
+++ b/tests/unit/gapic/securitycenter_v1beta1/test_security_center.py
@@ -155,7 +155,25 @@ def test_security_center_client_service_account_always_use_jwt(client_class):
     ) as use_jwt:
         creds = service_account.Credentials(None, None, None)
         client = client_class(credentials=creds)
-        use_jwt.assert_called_with(True)
+        use_jwt.assert_not_called()
+
+
+@pytest.mark.parametrize(
+    "transport_class,transport_name",
+    [
+        (transports.SecurityCenterGrpcTransport, "grpc"),
+        (transports.SecurityCenterGrpcAsyncIOTransport, "grpc_asyncio"),
+    ],
+)
+def test_security_center_client_service_account_always_use_jwt_true(
+    transport_class, transport_name
+):
+    with mock.patch.object(
+        service_account.Credentials, "with_always_use_jwt_access", create=True
+    ) as use_jwt:
+        creds = service_account.Credentials(None, None, None)
+        transport = transport_class(credentials=creds, always_use_jwt_access=True)
+        use_jwt.assert_called_once_with(True)
 
 
 @pytest.mark.parametrize(
@@ -5387,7 +5405,7 @@ def test_security_center_grpc_transport_client_cert_source_for_mtls(transport_cl
             "squid.clam.whelk:443",
             credentials=cred,
             credentials_file=None,
-            scopes=("https://www.googleapis.com/auth/cloud-platform",),
+            scopes=None,
             ssl_credentials=mock_ssl_channel_creds,
             quota_project_id=None,
             options=[
@@ -5496,7 +5514,7 @@ def test_security_center_transport_channel_mtls_with_client_cert_source(
                 "mtls.squid.clam.whelk:443",
                 credentials=cred,
                 credentials_file=None,
-                scopes=("https://www.googleapis.com/auth/cloud-platform",),
+                scopes=None,
                 ssl_credentials=mock_ssl_cred,
                 quota_project_id=None,
                 options=[
@@ -5543,7 +5561,7 @@ def test_security_center_transport_channel_mtls_with_adc(transport_class):
                 "mtls.squid.clam.whelk:443",
                 credentials=mock_cred,
                 credentials_file=None,
-                scopes=("https://www.googleapis.com/auth/cloud-platform",),
+                scopes=None,
                 ssl_credentials=mock_ssl_cred,
                 quota_project_id=None,
                 options=[
diff --git a/tests/unit/gapic/securitycenter_v1p1beta1/test_security_center.py b/tests/unit/gapic/securitycenter_v1p1beta1/test_security_center.py
index eaf64143..a048f6a6 100644
--- a/tests/unit/gapic/securitycenter_v1p1beta1/test_security_center.py
+++ b/tests/unit/gapic/securitycenter_v1p1beta1/test_security_center.py
@@ -160,7 +160,25 @@ def test_security_center_client_service_account_always_use_jwt(client_class):
     ) as use_jwt:
         creds = service_account.Credentials(None, None, None)
         client = client_class(credentials=creds)
-        use_jwt.assert_called_with(True)
+        use_jwt.assert_not_called()
+
+
+@pytest.mark.parametrize(
+    "transport_class,transport_name",
+    [
+        (transports.SecurityCenterGrpcTransport, "grpc"),
+        (transports.SecurityCenterGrpcAsyncIOTransport, "grpc_asyncio"),
+    ],
+)
+def test_security_center_client_service_account_always_use_jwt_true(
+    transport_class, transport_name
+):
+    with mock.patch.object(
+        service_account.Credentials, "with_always_use_jwt_access", create=True
+    ) as use_jwt:
+        creds = service_account.Credentials(None, None, None)
+        transport = transport_class(credentials=creds, always_use_jwt_access=True)
+        use_jwt.assert_called_once_with(True)
 
 
 @pytest.mark.parametrize(
@@ -7066,7 +7084,7 @@ def test_security_center_grpc_transport_client_cert_source_for_mtls(transport_cl
             "squid.clam.whelk:443",
             credentials=cred,
             credentials_file=None,
-            scopes=("https://www.googleapis.com/auth/cloud-platform",),
+            scopes=None,
             ssl_credentials=mock_ssl_channel_creds,
             quota_project_id=None,
             options=[
@@ -7175,7 +7193,7 @@ def test_security_center_transport_channel_mtls_with_client_cert_source(
                 "mtls.squid.clam.whelk:443",
                 credentials=cred,
                 credentials_file=None,
-                scopes=("https://www.googleapis.com/auth/cloud-platform",),
+                scopes=None,
                 ssl_credentials=mock_ssl_cred,
                 quota_project_id=None,
                 options=[
@@ -7222,7 +7240,7 @@ def test_security_center_transport_channel_mtls_with_adc(transport_class):
                 "mtls.squid.clam.whelk:443",
                 credentials=mock_cred,
                 credentials_file=None,
-                scopes=("https://www.googleapis.com/auth/cloud-platform",),
+                scopes=None,
                 ssl_credentials=mock_ssl_cred,
                 quota_project_id=None,
                 options=[