They are such a hot commodity, pharmacies and stores sometimes keep them behind glass.

They are the first line of defense against infection and disease - and are even linked to preventing depression and violence.

Desperate people will sometimes steal to get them.

No, this is not a story about illicit pills or drug abuse. It’s about disposable diapers, an item the poor need desperately.

Researchers are starting to realize “diaper need” not only causes obvious health problems for children, but leads to depression in moms and poor social and developmental outcomes for the child — even child abuse.

It is estimated that disposable diapers can cost up to $100 a month for one baby. On average, a newborn goes through eight to 10 diapers a day, said Melinda Ohlemiller, CEO of Nurses for Newborns.

Nurses with the organization see the diaper need firsthand with their clients but can offer minimal help.

To provide diapers for their mostly poor clients, Ohlemiller said, the organization would need 8,000 to 10,000 diapers a day. But the agency can supply only about 12 diapers to established clients on an emergency basis.

One of its clients, Catalina Martinez of Overland, Mo., said she was unable to work after having her second child. It’s been difficult to afford diapers for a newborn and a toddler on her boyfriend’s salary. She’s had to keep a diaper on her child longer than she should.

“I even have tried to get my oldest one to potty train. But she wouldn’t train yet.”

Last summer a study in the medical journal Pediatrics identified “diaper need” among the poor as a growing health and psychological risk for babies and their mothers.

The study determined that as many as 30 percent of poor parents in New Haven, Conn., struggled to afford diapers for their infants. It further linked diaper need as a factor causing maternal depression, which can also lead to poor outcomes for children.

“There’s just a great need and no one is calling attention to this,” said DiAnne Mueller, CEO of Crisis Nursery, a St. Louis-area child abuse prevention agency.

Crisis Nursery workers sometimes go door-to-door in poor neighborhoods asking people what they need. The answer is almost always the same: diapers and formula.

Although formula purchases can be federally subsidized, diapers are not covered by food stamps through the federal Supplemental Nutrition Assistance Program or the Special Supplemental Nutrition Program for Women, Infants and Children, known as WIC.

As a result, some food pantries are inundated with requests for disposable diapers. But the pantries don’t get steady donations of them and don’t always have them on the shelves. When they do, they fly out of the door, said Marcia Mermelstein, coordinator of the Harvey Kornblum Jewish Food Pantry in St. Louis.

“We’re giving people four to six diapers when in reality when most people buy a box of diapers, they’re getting 24 or 48. It’s like giving one tiny bar of soap a month. It’s not enough, it’s a token gesture,” Mermelstein said.

Families will take what they can get, she said.

“They’re taking diapers that are clearly too small and taping them together and using whatever they can.”

Although charitable agencies see the diaper need, they can’t make collecting and distributing diapers their first priority because it takes away energy and donations from their main services.

“Yes, we need diapers,” Mermelstein said. “But in the great scheme of things, we are a food pantry and the highest priority is to give food for survival.”

Some cities and regions have developed thriving diaper banks that collect and promote donated diapers and act as a clearinghouse to agencies like food pantries and community outreach centers.

According to the National Diaper Bank Network in Connecticut, about 100 established diaper banks operate nationwide. Happy Bottoms in Kansas City, Mo., for example, has distributed more than 1.5 million diapers to agencies that work with the poor.

But St. Louis is only in the beginning stages of developing such a resource.

Jessica Adams, a social worker, said she has filed the 501c paperwork for the St. Louis Area Diaper Bank and hopes to begin taking donations and making partnerships with agencies soon.

“I think the biggest issue in St. Louis is there’s not a roundtable conversation going on about diaper need,” she said. “So spreading the word to involve every agency will help everyone.”

Adams said she realized the need after she went through a divorce with a toddler and three older children. Money was scarce, and she relied on food pantries to get by.

“I had to call family members for money for diapers,” she said. “It’s humiliating, absolutely humiliating.”

Nurses for Newborns and Crisis Nursery workers hear of mothers rinsing out disposable diapers and reusing them. More commonly they see horrid cases of diaper rash.

Mueller said when a baby presents with bad rashes and even staph infections people unfairly conclude mothers are neglectful. But further questioning almost always reveals families are keeping the diapers on longer than they should because they don’t have enough.

“Diapers are mandatory. They’re not optional,” said Ohlemiller. “And yet families are making really hard decisions: Are we going to buy diapers or formula or are we going to buy food? That stress is putting a lot of hardships on families.”

Obtaining diapers can be more expensive for the poor because most don’t have enough cash on hand to buy diapers in bulk at a cheaper cost per diaper. So they resort to buying smaller packages at higher prices. If a family lacks a working car, they often buy diapers at the local convenience store, where the price skyrockets.

Ohlemiller said cheaper cloth diapers are typically not an option for the poor who often lack working washers and dryers. Coin laundries often ban diapers in their machines for sanitary reasons.

Child care centers are another obstacle. Day cares often ban cloth diapers for sanitary and logistical reasons. Mothers using day cares are often in a double bind: They can’t use cloth diapers, and if they run out of disposable diapers, they can’t send their child to day care. Without day care, moms can’t work.