diff --git a/src/main/java/org/ultramine/mods/privreg/regions/Region.java b/src/main/java/org/ultramine/mods/privreg/regions/Region.java
index 40beb94..4f57b68 100644
--- a/src/main/java/org/ultramine/mods/privreg/regions/Region.java
+++ b/src/main/java/org/ultramine/mods/privreg/regions/Region.java
@@ -149,7 +149,7 @@
 	@Override
 	public boolean addChild(IRegion region)
 	{
-		return children.add((Region) region);
+		return !children.contains(region) && children.add((Region) region);
 	}
 
 	@Override