diff --git a/coregrind/m_syswrap/syswrap-darwin.c b/coregrind/m_syswrap/syswrap-darwin.c
index 76ad8674d..02fca387b 100644
--- a/coregrind/m_syswrap/syswrap-darwin.c
+++ b/coregrind/m_syswrap/syswrap-darwin.c
@@ -2749,7 +2749,13 @@ PRE(posix_spawn)
    }
 
    // Decide whether or not we want to follow along
-   trace_this_child = VG_(should_we_trace_this_child)( (HChar*)ARG2 );
+   { // Make 'child_argv' be a pointer to the child's arg vector
+     // (skipping the exe name)
+     HChar** child_argv = (HChar**)ARG4;
+     if (child_argv && child_argv[0] == NULL)
+        child_argv = NULL;
+     trace_this_child = VG_(should_we_trace_this_child)( (HChar*)ARG2, child_argv );
+   }
 
    // Do the important checks:  it is a file, is executable, permissions are
    // ok, etc.  We allow setuid executables to run only in the case when