A US man dubbed the world's first pregnant man has given birth to a baby girl in the state of Oregon.

Thirty-four-year-old Thomas Beatie was born a woman, but underwent gender realignment surgery and is legally recognised as a man.

He was able to conceive because he retained his female organs when he underwent the sex change.

Mr Beatie has now revealed that he gave birth to a healthy baby girl on Sunday and plans to write a book about his experience.

A hospital source said: 'The baby girl is healthy and the mother - or father - and baby have been allowed to leave the hospital.'

Some reports suggest that Mr Beatie had a Caesarean section.

Mr Beattie announced his pregnancy in April on the Oprah Winfrey show, telling the presenter that he had always wanted to have children.

"I actually opted not to do anything to my reproductive organs because I wanted to have a child one day," he said at the time.

"I see pregnancy as a process and it doesn't define who I am."

Pregnant man reveals ultrasound to Oprah

Mr Beatie's obstetrician, Dr Kimberly James, told Oprah Winfrey in April: "This baby is totally healthy. This is what I consider a normal pregnancy."

Beatie has been married for five years to wife Nancy.