"The boy is healthy and the mother is doing well," Patrick Crimmins, spokesman for the state Child Protective Services, said of the noontime birth at Central Texas Medical Center.
The mother is "younger than 18," Crimmins said, and will remain with her new son in a nearby foster-care facility until a formal custody hearing will determine the pair's fate sometime before June 5. Crimmins declined to give any other details about the girl or where she and the baby would stay.
The girl's mother was present for the birth, but Crimmins said he didn't know who alerted her that her daughter was in labor.
Rod Parker, a spokesman for the Fundamentalist Church of Jesus Christ of Latter Day Saints, a renegade Mormon sect, contends the girl is 18. State officials have the girl on a list of minors taken into state custody.
Two armed state troopers and at least one person wearing the shirt of a Department of Family and Protective Services worker stood outside the maternity ward. A woman wearing the FLDS's trademark pastel prairie dress and upswept braided hair sat calmly in the nearby waiting room. All declined to comment, as did a woman who said she was the girl's attorney.
State officials raided the FLDS's Yearning For Zion Ranch in Eldorado on April 3. They took custody of 463 children on the belief that the sect's practice of underage and polygamous spiritual marriages endangered the children.
A number of girls first listed as adults were reclassified as minors as Child Protective Services, a division of Family and Protective Services, moved the children last week from a mass shelter in San Angelo to foster care facilities around the state, including some near San Marcos, in central Texas.
CPS spokesman Darrell Azar said he was unaware that an FLDS teen had gone into labor, but added that typically, a child born to a ward of the state becomes a ward of the state also.
Tela Mange, a spokeswoman for the Department of Public Safety, said she was unaware of troopers' involvement at the maternity ward, but said CPS often asks uniformed law enforcement to escort child welfare workers when needed.
On Monday, CPS announced that almost 60 percent of the underage girls living on the Eldorado ranch either have children or are pregnant.
Of the 53 girls between the ages of 14 and 17 who are in state custody, 31 either have given birth or are expecting, Azar said.
CPS said they are slowly getting some cooperation from girls, who initially claimed to be older than their actual age, reports CBS News correspondent Hari Sreenivasan.
Under Texas law, children under the age of 17 generally cannot consent to sex with an adult. A girl can get married with parental permission at 16, but none of these girls is believed to have a legal marriage under state law.
Church officials have denied that any children were abused at the ranch and say the state's actions are a form of religious persecution. They also dispute the count of teen mothers, saying at least some are likely adults.
All the children are supposed to get individual hearings before June 5 to help determine if they'll stay in state custody or if their parents may be able to take steps to regain custody. The first hearings have been set for May 19.
No one has been charged since the raid, which was prompted by a series of calls to a domestic abuse hot line, purportedly from a 16-year-old girl forced into a marriage recognized only by the sect with a man three times her age. That girl has not been found and authorities are investigating whether the call was a hoax.
Of the 463 children, 250 are girls and 213 are boys. Children 13 and younger are about evenly split 197 girls and 196 boys but there are only 17 boys aged 14 to 17 compared with the 53 girls in that age range.
The sect, which broke from the Church of Jesus Christ of Latter-day Saints more than a century ago, believes polygamy brings glorification in heaven. Its leader, Warren Jeffs, is revered as a prophet. Jeffs was convicted last year in Utah of forcing a 14-year-old girl into marriage with an older cousin and awaits trial on related charges in Arizona.