A Holdrege family is celebrating a very special birthday.

Lee and Rachel Woollen's "miracle babies" turn 1 this month. The quadruplets — three boys and a girl — were born Feb. 11, 2008.

The births at the Nebraska Medical Center in Omaha is believed to be the world's earliest delivery of surviving quadruplets. The babies were about four months premature, and each weighed less than 2 pounds.

Hospital officials say each baby had a 50 percent chance of survival, and the probability of all four surviving was 3.4 percent.

Rachel Woollen says her children have had few complications, other than viral infections and colds.

The boys are named Brett, Kaden and Cooper. Their sister is named Parker.