Many newborns have no desire to sleep through the night, much to the agitation of their parents. There are plenty of old wives tales about the best way to get children to sleep, but no matter how many warm bottles of milk and lullabies some parents provide, many babies simply will not stay asleep. Worried parents may recoil at the idea of leaving their baby alone to cry themselves to sleep, but a new paper suggests the method is effective without causing emotional damage.

A team of Australian researchers included 43 sets of parents in the study, each with a child between 6 and 16 months of age and one common complaint: their kid had trouble sleeping. The researchers split the parents into three groups. One got lessons in a sleep technique called graduated extinction — a technical name for crying it out. One learned a technique called bedtime fading where they put their child to sleep close to the time it usually dozed off and allowed it to remain in the room. The remaining group acted as a control and did not attempt any new technique.

The parents continued their various sleep interventions for three months. At the end of the period, researchers found that the cry-it-out infants fell asleep almost 15 minutes faster than the control group babies. Babies in the bedtime fading group nodded off approximately 12 minutes faster than the control group. However, the gradual extinction group bested the bedtime faders in the number of times the babies woke during the night and in total sleep time.

“When you are waiting for your baby to go to sleep, every minute counts,” Marsh Weinraub, professor of psychology at Temple University told CNN. She said that sleep gains for babies are an important benefit for their parents as well, but that the most important part of the study is that the sleep technique is safe for both the short and long term.

“Parents have been told by some experts that children’s stress levels will increase over time with these techniques and they will have behavioral problems, and this study shows very clearly, which I think is the first to do so, that there are no [poor] effects on children’s stress levels and … children in the intervention groups show less stress than children in the control condition,” Weinraub said.

The researchers measured the levels of the stress hormone cortisol in all of the babies during the study. They found that those participating in a new sleep intervention had lower cortisol levels during the experiment and didn’t show any signs of being more attached to their parents a year after the interventions. Parents also did not report more behavioral problems compared to the control group babies.

Study lead author Michael Gradisar, an associate professor of psychology at Flinders University in Adelaide, said that the sleep training doesn’t harm parent-child relationships, despite what critics say.

“We couldn’t find any differences,” he told The New York Times. “The more studies we get, the more confident we can feel that this is actually safe to perform.”

Source: Gradisar M, Jackson K, Spurrier N, Gibson J, Whitman J, Williams A, et al. Behavioral Interventions for Infant Sleep Problems: A Randomized Controlled Trial. Pediatrics. 2016.