Brett Bohner, 19, and his girlfriend, 18-year-old Chelsea Cormack were charged Thursday with aggravated assault and recklessly endangering a child.
State police say the couple took the baby to the emergency room at Hershey Medical Center on Wednesday, where doctors found she had a broken femur, collarbone and ribs. There also was blistering on the bottoms of her feet.
Police were called because the injuries did not appear to be accidental. During questioning by authorities, Bohner admitted breaking the baby's leg while changing her diaper.
Bohner and Cormack each failed to post $150,000 bail and are being held at Dauphin County Prison.