A couple were forced to endure a five-week wait for DNA results to find out if a newborn baby was theirs.
A midwife at Furness General Hospital told Sarah Wilson and Martyn Cahill, from Dalton-in-Furness, Cumbria, their new 6lb 12oz baby was a boy.
The couple named the child Ryan William, but later discovered they had a girl when giving her a bath, and feared they had the wrong baby.
Morecambe Bay Hospitals NHS Trust has apologised for the mistake.
The couple told friends and relatives they had a boy.
Miss Wilson said: "Lots of people had already bought boy's cards and blue clothes and they had to take them back and buy new ones.
"When she was born they said 'Congratulations, you've got a lovely baby boy' and the midwife had her in a towel straightaway so we didn't see her.
"The next day we gave her a bath and obviously we could tell straight away that she was a little girl."
Miss Wilson, 24, and Mr Cahill, 23, waited five weeks for DNA results to make sure the renamed Keira was theirs.
A spokeswoman for Morecambe Bay Hospitals NHS Trust said: "A mistake was clearly made, for which we are sorry.
"We are in the process of ascertaining how this happened to prevent a recurrence."