According to a study published this month in the Journal of International Society for Anthrozoology, women sleep better when their dog is in their bed with them.
They take up room, they scratch, lick and even snore... but regardless of all that, women who share their beds with dogs report less disturbed sleep and greater feelings of security and comfort.
Researchers found that women who sleep with cats did not show those benefits and reported disrupted sleep.
I don't see how co-sleeping works with any kid, pet or even spouse. I'd rather have the bed all to myself!