Why it's taking so long for the government to reunite the families it separated

And Health and Human Services Secretary Alex Azar basically admitted as much last week when he told reporters that his agency's system of shelters for unaccompanied minors wasn't designed to track what happened before kids ended up in custody.

"New efforts have had to be made to specifically determine whether a child was separated from a parent at the border, and to gather additional information about that purported parent," he said.

In court filings, officials have detailed the extensive lengths they're going to as a result of the judge's order. And Judge Dana Sabraw acknowledged their efforts on Friday, noting that the government had "devoted enormous resources in an attempt to comply, to reunify, and to make this happen." But even so, the judge hasn't granted any extensions on his deadlines -- yet.

Some parents have been released from ICE custody.

Authorities should have no trouble meeting the judge's deadlines when it comes to reuniting parents and kids under 5 years old who remain in custody, Justice Department attorney Sarah Fabian said last week. But she said they might need more time to reunite those children with parents who are no longer detained.

"If we're not aware of where the parent is," she said, "I can't commit to saying that reunification will occur before the deadline."

The ACLU's lead attorney in the family separations case has been adamant that the court already gave officials plenty of time -- and that the government should know the whereabouts of parents released from custody.

"It's startling that the record-keeping is not there. I don't understand why they don't know where the parent is. When they release a parent, they don't just let them walk out the door with no record. So there must be an address," the ACLU's Lee Gelernt said. "If the government is having trouble tracking down the parent, then private groups and advocates will do it."

And some parents have been deported.

So far, we know at least 12 parents were deported without their kids, according to the latest information released in court.

The total number of parents who were separated from their kids and then deported without them is likely far larger, since officials were only speaking about parents connected to the relatively small group of about 100 kids under age 5.

In a court filing last week the government said it would need more time to reunite deported parents with their kids "given the complexities involved in locating individuals who have been removed, determining whether they wish to be reunified with their child, and facilitating such a reunification outside of the United States."

Officials have said parents deported without their kids likely requested that their children remain in the US. Immigrant advocacy groups say they're concerned that some parents may have been coerced or may have signed documents they didn't understand.

HHS is conducting DNA tests to match up kids and parents.

Officials are still scrambling to sort out how many kids in custody were separated from their parents, and to confirm parent-child relationships. One method they're using: DNA tests.

The government says this takes time, but is a necessary step.

"HHS is working diligently to minimize the burdens of confirming parentage, and is expediting DNA verification. But given the possibility of false claims of parentage, confirming parentage is critical to ensure that children are returned to their parents, not to potential traffickers," a government court filing said last week.

Gelernt argued it shouldn't be necessary in all cases.

On Tuesday, Sabraw said he'd allow the government to conduct DNA testing "when necessary, when there is a legitimate, good-faith concern about parentage, or if there is a legitimate concern that the government will not meet the reunification deadline."

Releasing a child from custody is a lengthy process.

The ACLU attorney has argued that officials are going overboard in following "lengthy, cumbersome procedures," given that they're the ones who separated these parents and kids in the first place. The government has maintained that it has stringent steps it must follow to protect the health and safety of children in its care before releasing them.

Among them:

• Conducting background checks on sponsors, which includes extensive paperwork

• Making a "suitability" determination on whether the child will be well taken care of

• Potential home studies to make sure kids will be in a safe environment

"Our process may not be as quick as some would like, but there is no question that it is protecting children," said Chris Meekins, chief of staff for the Office of the Assistant Secretary for Preparedness and Response at HHS.

Sabraw said at a hearing Tuesday that the government should take a more streamlined approach in reuniting parents and children rather than following the steps it normally takes to place unaccompanied minors with sponsors.

"The idea of an application process doesn't fit in this context," the judge said. "The parent has a right to be reunified and it's the government's obligation to make it so."