From PEOPLE Magazine Click to enlarge
In a Los Angeles backyard festooned with balloons, Josie Hull and Teresa Cajas celebrated their 11th birthday on July 14 in matching pink frilly dresses and sparkly tiaras. The sisters share the same broad, open faces and jet-black hair. But while Josie belts out a karaoke version of Lady Gaga's "Born This Way" and leads a parade of pals across the lawn in her motorized walker, Teresa watches from a wheelchair, unable to move or speak. Still, she cracks a smile, and that's enough for her twin. "You can tell she's happy," Josie says. "My sister and I have been blessed. We're lucky."

It took love as well as luck to get to this day. Born joined at the head in a Guatemalan village to Wenceslao, 31, and Leticia Quiej-Alvarez, 32, the girls were not expected to live more than a year. But with help from the nonprofit Healing the Children, the family was flown by private jet to Los Angeles. There the twins underwent a grueling 23-hour separation surgery on Aug. 5, 2002, at UCLA Medical Center, which made international headlines (PEOPLE, Aug. 26, 2002).

The joy at that successful operation was followed by a tougher reality. Back in Guatemala, Teresa contracted a brain infection that left her in need of round-the-clock care. Josie battled seizures and other medical problems. To ensure their daughters' survival, the Quiej-Alvarezes made the gut-wrenching decision to allow their American hosts-Jenny Hull, 41, for Josie, and Werner, 51, and Florie Cajas, 50, for Teresa-to adopt the girls. (The birth parents visit twice a year.)

Now Hull and the Cajases are like one family, getting the girls together several times a week for physical therapy, shared meals and just plain sister time. "They have a deep love," Hull says. "It is beautiful."