Treating children with cystic fibrosis over the years, Lael Yonker, M.D., observed that while medications often helped for a short time, the genetic lung disease eventually worsened. This motivated her to investigate the role of the immune system in children with lung diseases.

“In both cystic fibrosis and postinfection illnesses, my research focuses on the same big questions: Why do some infections cause severe or lasting disease, and how does the immune system sometimes cause harm instead of healing?” said Dr. Yonker, Associate Professor of Pediatrics.

Dr. Yonker’s desire to answer these questions and improve children’s health will play a significant role in her new position as Chief of the Division of Pediatric Pulmonology and Sleep Medicine. She joined UTSW in November. She joined UTSW in November. At Children’s Health, she also serves as Chief of the Division of Pediatric Pulmonology and Sleep Medicine and Medical Director of the Children’s Pulmonary Translational Research Center.

A nationally recognized physician-scientist, Dr. Yonker said she was drawn to the specialty of pediatric lung disease by her ambition to impact youth health. Even small changes in care can make a big difference in a child’s lifetime health, she said.

“I love taking care of children and helping them breathe more easily,” Dr. Yonker said. “When a child’s cough improves, or breathing becomes easier, they can play, learn, and enjoy life again.”

Dr. Yonker earned her medical degree from the University of Massachusetts Medical School. She completed a residency in pediatrics and received advanced training through a pediatric pulmonary fellowship, both at Mass General Brigham. She has received research funding from the National Institutes of Health, multiple organizations that include the Cystic Fibrosis Foundation, and industry partners.

Certified by the American Board of Pediatrics, she joined the UT Southwestern faculty in 2025. She previously served at Mass General Brigham, where she was Director of the Cystic Fibrosis Center, co-Director of the Cystic Fibrosis Therapeutic Development Center, co-Director of the Pulmonary Genetics Program, and Principal Investigator for the Pediatric COVID-19 Biorepository.

She has received many honors, including the Robert B. Mellins, M.D. Outstanding Achievement Award from the American Thoracic Society and designation as an Emerging Leader from the National Academy of Medicine.

One of her goals as Division Chief is to make it easier for children with breathing problems to see a lung specialist.

“I want to make sure we give the best care possible, while also helping discover better tests and treatments,” she said. “By doing this, we can improve the health of children in the Dallas-Fort Worth area and beyond.”