Brenna is a biological anthropologist and archaeologist. Her research focuses on childhood, health, and growth in the past. Active research areas include dental anthropological approaches to understanding early development, health and growth in the transition to sedentary and agricultural living, and the history and practice of archaeology. She writes books for popular audiences on bones and teeth including 'Built on Bones: 15,000 Years of Urban Life and Death' and 'Growing Up Human: the Evolution of Childhood'. She is a Fellow of the Society of Antiquaries and is also 1/4 of Team TrowelBlazers, a project advocating for equality and the recognition of women's contributions to the digging sciences.