Young migrant mothers in border detention facilities described feeling hungry, cold, and terrified because their babies were sick.
The Texas Civil Rights Project found that 272 families have been separated at a single Texas courthouse since June.
Children are being turned away at the border and face dangerous, life-threatening situations, experts say.
Childhood trauma can stunt cognitive development and alter the structure of young brains in profound and permanent ways.
Customs and Border Protection agents take away essentially all possessions carried by undocumented immigrants. It's not clear if they ever get them back.
"This is as horrific a policy as I've seen in 25-plus years doing civil rights work," an ACLU attorney said.