Dr. William Benitz walks past the rows of clear plastic isolettes in the neonatal intensive care unit at Lucile Packard Children's Hospital at Stanford University.

There's little room to navigate — the space is jampacked with beeping machines and ventilators. The health team in the unit can care for as many as 70 fragile infants. One tiny, pink baby girl here today was born weighing 13 ounces.

"A can of Coke is 12 ounces. So imagine a baby who could almost curl up in a fetal position and fit inside a Coke can," says Benitz, the hospital's chief of neonatology.

He first came to Stanford 42 years ago as a medical student, and says the ability of doctors today to save babies this small feels like something of a miracle.

But as far as medical technology has come, some of the sickest and most premature babies who pass through his NICU won't make it, Benitz says. Others will go on to have severe, lifelong disabilities. Only 30 percent of the babies born at 24 weeks of gestation, for example, survive without impairments.

One of the most difficult parts of Benitz's job is determining how much treatment to give babies like these, and figuring out when it's time to let them go. More and more, doctors like Benitz are looking to parents to help make these decisions, based on the parents' values and preferences.

The American Academy of Pediatrics recently advised that parents should be given wide latitude in deciding how aggressive doctors should be with treatment in cases where their child is at high risk of death or serious disability. In practice, this means parents willing to raise a child with severe disabilities might elect to pursue more aggressive care than parents who do not want to take on that risk.

That's a big change. When Benitz first started at Stanford in 1973, doctors were considered the absolute authorities in life-and-death decisions, he says. They consulted with colleagues and decided how much intensive care to give, based on what they thought was the likeliest outcome. Often these doctors didn't even tell the parents about the decision before taking action.

"It never occurred to anyone that that might be a reasonable conversation to have," Benitz says. "We were in unexplored territory."

As technology improved and doctors tried to save sicker babies, and some born even earlier in gestation, there were new decisions to make: Should the health team put the tiny child on a ventilator? Attempt heart surgery? Those interventions helped many infants survive. Others did not fare as well.

"A lot of them ended up with significant impairments," Benitz recalls. And doctors started to get pushback. "In the mid-80s we began to hear from families that maybe that wasn't consistent with their goals for their children."

Packard Children's Hospital social worker Jane Zimmerman, who works with Benitz, says many doctors back then were trying to protect parents.

"The rationale for it," she says, "was they didn't want parents to have to take on that lifelong responsibility at having felt they made a decision that resulted in their child's death."

But some parents were angry that doctors had stopped intensive care without consulting them. Others were furious that they had not been given the option to end treatment of babies who ended up with severe cognitive and physical disabilities. Some filed lawsuits accusing doctors of causing their children "wrongful death" or "wrongful life."

Such cases coincided with a larger movement in which adults fought for more say in their own medical care. By the mid-90s, parents in the NICU had become much more involved in decision-making for their babies.

The choices parents face are often heartbreaking. In May 2015, Chris and Karin Belluomini had a daughter they named Joy. She was born with Down syndrome, multiple heart defects and fluid around her lungs. From the very start, doctors at Packard gave them the option of providing just comfort care, treatments that would soothe their daughter and relieve any suffering, but weren't aimed at fixing her heart problems.

On one hand, the Belluominis, whose child was a patient of Benitz and Zimmerman, have strong faith in God and were more than willing to raise a child with disabilities, even severe ones.

On the other hand, they didn't want their daughter to suffer unnecessarily.

Their final decision was to have doctors do everything they could — up to a point.

"We let them know, if her heart stopped, we did not want her to be resuscitated," recalls Karin Belluomini. "We just wanted her to be comfortable."

Joy remained in the NICU for three difficult weeks. By the end, her blood oxygen levels were so low that the doctors said she could die at any time — possibly when her parents weren't there. That's when the Belluominis decided to remove life support, so that Joy could die peacefully in their arms, disconnected from the tubes and needles.

Both parents say it was difficult to even imagine not being a part of such decisions.

"As a parent, you just want to do everything and anything to protect your child," says Karin. "So to be able to really understand her condition and how it's affecting her, and to know that we did have a say in that, was extremely important."

"You kind of don't want that responsibility," adds Chris, "and would rather have someone say or do it for you. But in the end, I wouldn't want it to have been any other way."

Copyright 2016 Kaiser Health News. To see more, visit Kaiser Health News.