Co-sleeping
Co-sleeping, also called the family bed, is a practice in which babies and young children sleep with one or both parents.  It is standard practice in many parts of the world outside of North America, Europe and Australia, although sometimes children may crawl into bed with their parents.  One 2006 study of children age 3-10 in India reported 93% of children co-sleeping.  Co-sleeping was widely practiced in all areas up until the 19th century, until the advent of giving the child his or her own room and the crib.  In many parts of the world, co-sleeping simply has the practical benefit of keeping the child warm at night.  Co-sleeping has been relatively recently re-introduced into Western culture by practitioners of attachment parenting. A 2006 study of children in Kentucky in the United States reported 15% of infants and toddlers 2 weeks to 2 years co-sleeping.
Proponents variously believe that co-sleeping saves babies' lives (especially in conjunction with nursing), promotes bonding, lets the parents get more sleep, facilitates breastfeeding, and protects against sudden infant death syndrome ("SIDS"). Older babies can breastfeed during the night without waking their mother. Opponents argue that co-sleeping is both stressful and dangerous for the baby, and argue that modern-day bedding is not safe for co-sleeping. They point to evidence that co-sleeping may increase the risk of SIDS, and argue that the parent may smother the child or promote an unhealthy dependence of the child on the parent. On the other side, they note that this practice may interfere with the parents' own relationship in terms of reducing both communication and sexual intercourse at bedtime.
According to some advice, co-sleeping is likely to end after a year or two if the child is not forced to co-sleep. The child may choose a place of their own, possibly on a surface that would appear to be uncomfortable by adult standards. Hot weather and weaning can encourage this natural separation.

# Safety and health
Co-sleeping triggers conflicting advice among health care professionals.  The U.S. Consumer Product Safety Commission warns against it.   However, many pediatricians, breast-feeding advocates, and others have harshly criticized the CPSC recommendation.  

## Advantages
There may be health advantages to co-sleeping.
One study reported mothers getting more sleep by co-sleeping and breastfeeding than by other arrangements.
It has been argued that co-sleeping evolved over five million years, that it alters the infant's sleep experience and the number of maternal inspections of the infant, and that it provides a beginning point for considering possibly unconventional ways of helping reduce the risk of SIDS.
Stress hormones are lower in mothers and babies who co-sleep, specifically the balance of the stress hormone cortisol, the control of which is essential for a baby's healthy growth.
In studies with animals, infants who stayed close to their mothers had higher levels of growth hormones and enzymes necessary for brain and heart growth.
The physiology of co-sleeping babies is more stable, including more stable temperatures, more regular heart rhythms, and fewer long pauses in breathing than babies who sleep alone.
Co-sleeping promotes long-term emotional health.  In long-term follow-up studies of infants who slept with their parents and those who slept alone, the children who co-slept were happier, less anxious, had higher self-esteem, were less likely to be afraid of sleep, had fewer behavioral problems, tended to be more comfortable with intimacy, and were generally more independent as adults.

## Dangers
Co-sleeping is known to be dangerous when a parent smokes, but there are other risk factors as well.  Web sites give advice on reducing the risks. 
Safebedsharing.org . Some common advice given is to keep a baby on its back, not its stomach, that a child should never sleep with a parent who smokes, is taking drugs (including alcohol) that impede alertness, or is extremely obese.  It is also recommended that the bed should be firm, and should not be a waterbed or couch; and that heavy quilts, comforters, and pillows should not be used.  Young children should never sleep next to babies under nine months of age. It is often recommended that a baby should never be left unattended in an adult bed even if the bed surface itself is no more dangerous than a crib surface. There is also the risk of the baby falling to a hard floor.

## Products
There are several products which can be used to facilitate safe co-sleeping with an infant.
- bassinets that attach to the side of an adult bed, and which have barriers on three sides, but are open to the parent's bed.
- bed top co-sleeping products (Family Sleeper) designed to prevent baby from rolling off the adult bed and absorbing breastfeeding and other night time leaks.
- side rails to prevent the child from rolling off the adult bed.
- co-sleeping infant enclosures which are placed directly in the adult bed.

# Prevalence
A study of a small population in Northeast England showed a variety of nighttime parenting strategies and that 65% of the sample had bedshared, 95% of them having done so with both parents.  The study reported that some of the parents found bedsharing effective, yet were covert in their practices, fearing disapproval of health professionals and relatives.
Additionally, a National Center for Health Statistics survey from 1991 to 1999 found that 25% of American families always, or almost always, slept with their baby in bed, 42% slept with their baby "sometimes", and 32% never co-slept with their baby.

# Further reading
- Jackson, Deborah. Three in a Bed: The Benefits of Sharing Your Bed with Your Baby, New York: Bloomsbury, 1999.
- Thevenin, Tine. The Family Bed, New Jersey: Avery Publishing Group, 1987.