diff --git a/Lib/test/test_uuid.py b/Lib/test/test_uuid.py
index c22b6af..43fa656 100644
--- a/Lib/test/test_uuid.py
+++ b/Lib/test/test_uuid.py
@@ -457,6 +457,34 @@
             equal(u, uuid.UUID(v))
             equal(str(u), v)
 
+    def testIssue8621(self):
+        import os
+        import sys
+        if os.name != 'posix':
+            return
+
+        # On at least some versions of OSX uuid.uuid4 generates
+        # the same sequence of UUIDs in the parent and any
+        # children started using fork.
+        fds = os.pipe()
+        pid = os.fork()
+        if pid == 0:
+            os.close(fds[0])
+            value = uuid.uuid4()
+            os.write(fds[1], value.hex.encode('latin1'))
+            os._exit(0)
+
+        else:
+            os.close(fds[1])
+            parent_value = uuid.uuid4().hex
+            os.waitpid(pid, 0)
+            child_value = os.read(fds[0], 100).decode('latin1')
+
+            self.assertNotEqual(parent_value, child_value)
+
+
+
+
 
 def test_main():
     support.run_unittest(TestUUID)
diff --git a/Lib/uuid.py b/Lib/uuid.py
index b4554e4..fda9fe1 100644
--- a/Lib/uuid.py
+++ b/Lib/uuid.py
@@ -427,6 +427,19 @@
         if hasattr(lib, 'uuid_generate_time'):
             _uuid_generate_time = lib.uuid_generate_time
 
+    # The uuid_generate_* functions are broken on MacOS X 10.6, as noted
+    # in issue #8621 the function generates the same sequence of values
+    # in the parent process and all children created using fork (unless
+    # those children use exec as well).
+    #
+    # Assume that the uuid_generate functions are broken from 10.6 onward,
+    # the test can be adjusted when a later version is fixed.
+    import sys
+    if sys.platform == 'darwin':
+        import os
+        if int(os.uname()[2].split('.')[0]) >= 10:
+            _uuid_generate_random = _uuid_generate_time = None
+
     # On Windows prior to 2000, UuidCreate gives a UUID containing the
     # hardware address.  On Windows 2000 and later, UuidCreate makes a
     # random UUID and UuidCreateSequential gives a UUID containing the
diff --git a/Misc/NEWS b/Misc/NEWS
index e1ce08b..b25f110 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -348,6 +348,9 @@
 Library
 -------
 
+- Issue #8621: uuid.uuid4() returned the same sequence of values in the
+  parent and any children created using ``os.fork`` on MacOS X 10.6.
+
 - Issue #8567: Fix precedence of signals in Decimal module: when a
   Decimal operation raises multiple signals and more than one of those
   signals is trapped, the specification determines the order in which