Why babie's smile ,when they are in deep sleep?

My baby is 2months now, I also noticed that he smile even when he is in deep sleep. I do not know really the exact answer to this but for my own believe. babies who are smiling or crying even in deep sleep is just having a dream. Everytime I saw my son smiling while sleeping I would think that "My baby is just dreaming that I really love him and I'm taking care of him"

My son is like that also when he was a baby. He smiles while sleeping and sometimes he grins. It was very fun to look at those facial expressions. Until now that he is 21 months old, sometimes he smiles when he is sleeping and a smile comes out of my face. It's very nice to witness those smiles from your baby's face!

I read this little piece and thought it was interesting. Since you posted this discussion. Why Do Babies Smile So Much? Most parents won't witness their baby's first smile for 8 to 12 weeks. But usually by the third month, most babies will flash their first grin -- and melt their parents' hearts. These earliest smiles are probably unintentional facial movements, but our gushing responses to them virtually ensure we'll see more of the same. For the preverbal infant, smiling provides a means to communicate: when your baby smiles and you smile back, you're practicing the same type of back-and-forth exchange that happens later with language. From about 4 to 6 months, babies will smile at nearly everyone they encounter. But after that, many babies begin to develop stranger anxiety and will smile more discriminately, reserving their biggest crinkle-eyed, raised-cheek smiles for their parents and other loved ones, while greeting strangers with a more tentative, low-key smile, if any. But the wonderful thing about all babies' smiles -- big or small -- is that they're invariably genuine. Whereas adults may smile to be polite, when babies smile, they're happy.

My daughter did the same thing. She had all kinds of facial expressions when she was asleep. I was always told that when she does this she's dreaming. It makes sense to me. Adults do it when they sleep too.

As hard as it might be for you to believe - it's probably not likely to be an 'actual' smile. Newborn's are usually full of gas & that's the kind of expression you get when they're passing gas or at least trying to :) If he is trying to pass gas but cant, that would explain the crying as he is probably sore if the wind doesn't come out, they end up with bad tummy aches & then need help to get it up. I hope that helps you some though, you really do have a few more weeks to go before your baby is likely to 'properly' smile at you - but when he does, you'll know it's real & not gas or anything!