I think co-sleeping is great as long as one is aware of the problem of sleep association. When a baby falls asleep, they check their environment. When they wake at night, often several times a night, and the environment has changed, they will try to set it right, but will cry when they cannot.

What we associate with sleep can become a very difficult pattern to break. For many adults, it might be a certain routine before bedtime, a certain side of the bed, or even what they wear. But adults can fix their environment if it changes and go back to sleep. Babies cannot.

I think co-sleeping is great. At some point however, as babies mature into toddlers, they must learn how to settle themselves to sleep.