Louisa Bradshaw Jessop maintains she is 22, but the department has her classified as 17. She has two other children, ages 3 and 2, and is in state custody with them after an April 3 raid on her home, the YFZ Ranch in Eldorado.
Texas officials raided the ranch, home to members of the Fundamentalist Church of Jesus Christ of Latter Day Saints, to investigate an abuse claim. Child welfare officials say they found evidence of a pattern of abuse at the ranch, including sex with underage girls, that justified removal of all children.
The birth brings the number of children in custody to 465.
Jessop's husband, Rulan Danial Jessop, 24, filed a habeas corpus petition in Austin last Wednesday that argues his wife is being improperly detained by the state. The couple provided a birth certificate, driver license and other documents as proof of Louisa Jessop's age.
Patricia Matassarin, who represents Louisa Jessop, is scheduled to appear again in court on the matter Thursday.
Parker said the plan to move the mother and infant was a "forum shopping maneuver" that would have allowed the state to file custody papers on the baby in San Angelo.
"Why else would they move a 6-hour-old baby halfway across Texas in the middle of the night when they have dozens of FLDS children in shelters in Austin?" Parker said.
Texas DFPS spokesman Patrick Crimmins said the agency would not comment on the issue. The agency filed a similar petition two weeks ago to take custody of another baby born to a woman also deemed to be a minor.
The raid was triggered by a San Angelo shelter that said it had been contacted by a caller claiming to be a 16-year-old abused by her polygamous husband at the ranch. The caller has never been located among the children and the calls are now being investigated as a possible prank by a Colorado woman.