Federal officials are also warning that they are having to use less vigorous parental vetting methods in order to meet the court-ordered deadline.
The Department of Homeland Security says the man said the girl was actually his niece and that he was using a fake document to say she was his daughter.
The Trump administration's struggle to meet a judge's order reveals the extent of its lack of planning when it implemented its "zero tolerance" policy.
The Department of Health and Human Services said the tests are intended to speed reunifications following a court order, but they raise questions about what planning went into the separation policy.
For teens attending their hearings in a Texas immigration court, legal advice came primarily from the judge.
Legal groups working with detained families say they haven't seen any evidence that such a database exists.
"Their children have been taken from them and they are being made to go through hoops and hurdles to get them back."
The administration separated more than 2,300 children from adults they were traveling with while illegally crossing the southern border.
A judge suggests the need to order reunions is unnecessary because of Trump's executive order. But that appears to be wishful thinking.
One day after the president issued an executive order on family separation, his administration seemed intent on offering confusing commentary.
One woman pretended to wash car windows until she was close enough to the US to ask for asylum. Another boarded a US-bound bus, then asked for asylum when a border agent asked for her documents.
"It is still very early and we are awaiting further guidance on the matter."
"It's about keeping families together, while at the same time being sure we have a very powerful very strong border and border security," Trump said.
The Trump administration's claim that there is a crisis on the southwest border relies on a statistical comparison that masks a decline in border arrests over the past two decades.
Immigration authorities have no intention of reuniting parents separated from their kids until they're about to be deported or released from detention.
"We saw the fear in the eyes of these children who are wondering when they're going to see their parents again."
The number was current as of May 31. More certainly have been separated from their parents since.
Some of what you're reading is new, some has been going on for a long time now.
Immigration advocates denounced the decision, which likely will affect the claims of thousands of women.
Immigration authorities said the move is in response to the current surge in illegal border crossings and implementation of the US Department of Justice’s zero-tolerance policy.