It's one of those dilemmas that keep parents up at night. Your baby is wailing. Do you let them 'cry it out' or do you rush in to soothe them? And how long should you give it before you go in to them? Well, the jury has been out for some time. But now science claims to have the answer.

According to an article in Science Daily, a study published in Developmental Psychology maintains that the majority of infants be left to self-soothe and fall back to sleep on their own. 

"By six months of age, most babies sleep through the night, awakening their mothers only about once per week. However, not all children follow this pattern of development," said Temple psychology professor Marsha Weinraub.

In a study of more than 1,200 infants aged six to 36 months, Weinraub's team monitored sleep patterns at various stages by dividing babies into two groups: "sleepers and transitional sleepers."

"If you measure them while they are sleeping, all babies—like all adults—move through a sleep cycle every 1 1/2 to 2 hours where they wake up and then return to sleep," said Weinraub. "Some of them do cry and call out when they awaken, and that is called 'not sleeping through the night.'"

By six months of age, 66 percent of "sleepers" did not awaken, while 33 percent woke up every night of the week, and only twice a week by 24 months. More of the "transitional sleepers" were boys rated higher in terms of irritability and distractibility. Surprisingly, they were more likely to be breastfed. Their mothers were also more likely to be depressed, a condition perhaps exacerbated by sleep deprivation.

Weinraub believes such findings reflect the correlation between "difficult temperaments and early sleep problems." She suggests that families with babies experiences sleeping problems beyond 18 months should seek advice.

She stresses the importance of letting babies learn to fall asleep on their own. "When mothers tune in to these night time awakenings and/or if a baby is in the habit of falling asleep during breastfeeding, then he or she may not be learning to how to self-soothe, something that is critical for regular sleep." 

So while we may think we are doing the best for baby by rushing in to comfort him with a breast or a cuddle, we may in fact be prolonging wakefulness. 

"The best advice is to put infants to bed at a regular time every night, allow them to fall asleep on their own and resist the urge to respond right away to awakenings."

What do you make of this study? Are you a fan, or an enemy, of the cry it out approach?