US media report a Californian woman who gave birth to octuplets earlier this week already has six children.
The eight babies were delivered nine weeks early by Caesarean section in a hospital near Los Angeles on Monday.
The mother has not been named, but US media are quoting family members as saying she already has six other children, including twins.
Doctors say the eight babies are making good progress and are expected to stay in hospital for several more weeks.
Although the babies' mother asked doctors to keep her details confidential, a family acquaintance gave clues to her identity to CBS News.
Shortly afterwards, media camped outside a house in Whittier, near Los Angeles.
The Associated Press news agency spoke to a man identified as the babies' grandfather, who was with two children. AP reported the children said they were excited to have eight new siblings.
The Los Angeles Times later carried an interview with a woman identified as the babies' grandmother, who said her daughter already had six young children and never expected the fertility treatment she had received would result in eight more babies.
Officials at the Kaiser Permanente Medical Center, near Los Angeles, said the woman was already 12 weeks pregnant when she came to them.
The hospital has declined to say whether the mother became pregnant through fertility treatments.
The eight babies were delivered by a team of 46 doctors, nurses and assistants in the space of five minutes.
Their mother is the second person recorded in the United States to have delivered a set of living octuplets.
The BBC reports the last octuplets known to have survived birth in the US were born in Houston in 1998. One died a week later.