diff --git a/bin/add_custom_gene.py b/bin/add_custom_gene.py
index 5c228bc..cb59988 100755
--- a/bin/add_custom_gene.py
+++ b/bin/add_custom_gene.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 # -*- coding: utf-8 -*-
 """
 Add the custom human genes which are missing from the Ensembl database.