Which side should babies sleep on?

Of course, this is a big deal in the US these days – you’re supposed to put them on their back.  When he was little and swaddled, we put him on his side. Now we always put Kinsley on his back to sleep. He’s been able to roll over for over three weeks now, but doesn’t do it much – doesn’t seem to like the sensation.  This morning he was really tired, but complained really loudly when I put him down.  As usual, knowing he was tired, I left him.  Later when it was quiet I went in to get something, thinking he was asleep.  Almost.  He didn’t look at me but he was still moving a bit.  He was just settling himself down on his stomach. Guess he gets to decide now which side he sleeps on!

Edit: While I was writing that, Kinsley woke up much too soon for a growing boy.  When he didn’t settle down after some time, I went in to check on him.  He was on his back again. Almost felt like I imagined it. Apparently he’s been practicing when we aren’t looking.