Researchers at ETH Zurich have developed a volumetric bioprinting method to create 3D replicas of human lactating breast tissue, enabling in vitro study of milk synthesis. Using laser sculpting within a photosensitive liquid derived from bovine udder tissue, mammary epithelial cells isolated from human breast milk were cultured to form functional ducts producing key milk components such as β-casein and milk fat globules. This pioneering platform offers new avenues for studying lactation biology and female health, overcoming prior challenges in culturing these specialized cells outside the body.