When Maria de Jesus and Maria Teresa Quiej-Alvarez were wheeled into surgery at UCLA's Mattel Children's Hospital on Aug. 5, no one knew if they would come out alive. Joined at the head, the then-12-month-old Guatemalan twins faced a 22-hour procedure to divide their skulls. Three months later, says Dr. Jorge Lazareff, the head of UCLA's neurosurgical team, "we all have reason to celebrate."

Though Maria Teresa lags behind her sister, both are recovering beautifully. They can sit up and grasp rattles; Maria de Jesus says "bye-bye." They are set to return to their homeland with their parents—farmworkers Wenceslao, 21, and Alba, 22—within days. After another year of bone grafts and physical therapy, doctors hope the twins will lead normal lives. "I'm grateful to everyone," says Wenceslao. "They made the miracle happen."

UCLA has covered most of the $1.5 million in medical costs, according to Healing the Children, the group that arranged the surgery. But the girls' greatest allies may be each other. Lying beside Maria Teresa, "Maria de Jesus will reach over and hold her hand," nurse Margo Goldman reports. "You know she's watching out for her."