Should you let a baby cry itself to sleep? It's a question anxious mums and dads have fretted about forever.
Researchers in Australia have been studying the baby sleep question and they've come up with an actual answer.
A Flinders University's study has found two training methods improved babies' sleeping habits without detrimental effects on the infant or their family.
The most successful technique was controlled crying, where babies learn to self-soothe. On average, infants fell asleep 13 minutes sooner.
"The other benefit was that they weren't waking up as much during the night as well," says Dr Michael Gradisar.
There was no evidence to suggest it caused long-term problems or parent-child attachment issues.
"It's the first study to really show -- does controlled crying lead to these increases in the cortisol stress hormones -- and essentially we can't find evidence of that," Dr Gradisar says.
The other, gentler method was bedtime fading, where parents delay an infant's bedtime; however, the results weren't quite as good.
On average, babies in the bedtime fading group fell asleep 10 minutes faster than usual, but surprisingly there were no changes in the number of night-time awakenings.
Dr Gradisar admits more research is needed to shore up the findings, but he hopes parents become more open to controlled crying.