I have a sister-in-law who bought into the co-sleeping idea that really seems to be taking off. They now have a seven year old son whom they are still "trying" to get to stay in his bed all night. They have a four- year-old daughter who stays in her bed with no problems. They learned the hard way with the first child-bad idea. I didn't do it with mine. You love, nurture and care for your children all day. A little separation at night never hurt anyone. When they were tiny, a bassinette in the bedroom with me was fine. Obviously, if there are health issues with a baby, then things change. I found this article:
co-sleeping (Here is an exerpt)
Co-sleeping (AKA "the family bed") refers to the practice of allowing children to sleep with their parents habitually. It is widely practiced in certain ethnic and racial groups in the US; the incidence is lowest in white upper- and middle-class families. Co-sleeping is promoted actively by many ardent advocates of breastfeeding, as well as by some physicians (notably William Sears, M.D., author with his wife of several parenting books), who advocate the "family bed." They claim a variety of unsubstantiated benefits for this practice.
The cultural roots of co-sleeping have more to do with economic necessity than anything else. The observation that most of the world's children sleep with their parents is simply a restatement of the fact that most of the world's children live in cramped quarters. The advantages claimed for co-sleeping are many but mainly center on purported significant emotional benefits to the child. These supposed benefits have not been actually documented. There is no evidence that cultures that practice co-sleeping produce adults who are any better adjusted (or worse) than those cultures who practice separation.
A recent study of co-sleeping by breast feeding infants showed that the co-sleeping infants nursed more frequently at night (surprise) and had more night wakings even when they slept apart from the mother. This reinforces my observations and my conclusion that habitually allowing babies to sleep with the parents is not a good long-term plan for average middle-class families in western industrial societies, as it leads to a host of sleep-related behavior problems later on in infancy and the toddler years. I have found it true in counselling mothers using my video that co-sleeping can lead to what is perceived by the parents as very dependent and demanding behavior from the child at night.