diff --git a/setup.py b/setup.py
index 821fda5..73af9eb 100644
--- a/setup.py
+++ b/setup.py
@@ -181,6 +181,7 @@
   pymodinit_type = 'PyObject*' if PY3 else 'void'
   pymodinit = '__attribute__((visibility ("default"))) {}'.format(pymodinit_type)
   DEFINE_MACROS += (('PyMODINIT_FUNC', pymodinit),)
+  DEFINE_MACROS += (('GRPC_POSIX_FORK_ALLOW_PTHREAD_ATFORK', 1),)
 
 # By default, Python3 distutils enforces compatibility of
 # c plugins (.so files) with the OSX version Python3 was built with.
diff --git a/src/core/lib/iomgr/fork_posix.cc b/src/core/lib/iomgr/fork_posix.cc
index a55b3a3..f3cfd14 100644
--- a/src/core/lib/iomgr/fork_posix.cc
+++ b/src/core/lib/iomgr/fork_posix.cc
@@ -81,7 +81,9 @@
 
 void grpc_fork_handlers_auto_register() {
   if (grpc_fork_support_enabled()) {
+#ifdef GRPC_POSIX_FORK_ALLOW_PTHREAD_ATFORK
     pthread_atfork(grpc_prefork, grpc_postfork_parent, grpc_postfork_child);
+#endif  // GRPC_POSIX_FORK_ALLOW_PTHREAD_ATFORK
   }
 }