A baby weighing just 275 grams has been born in Germany and survived, the lowest weight for a viable birth of a boy ever recorded, doctors said on Thursday.

Doctors normally assume that survival is impossible at birth weights below 350 grams.

The little boy was born in June last year in the 25th week of pregnancy, said Stefan Weller, a spokesman for the University of Goettingen Hospital. He spent six months in intensive care and was finally discharged in December after growing to 3.7 kg.

Mr. Weller said doctors had checked every available record worldwide of premature births and found no viable birth at a lower weight.