I take little z out in only his diaper...alll the time. He looks so cute in the sling cuz it looks like he isn't wearing anything! And he doesn't wear a hat...and I've never put sunscreen on him...and he's never been burnt. And he has a tan!!! And the only way you can tell he is tanned is the wrinkles/folds on his ankles are white when you stretch his feet out!!