Justyna Miszkiewicz still remembers the hush that fell over the lab when the first micro-CT scan of a 70,000-year-old Neanderthal infant’s molar flickered to life on the screen—its internal structure, unseen for millennia, revealing faint scars of early life stress. The tiny tooth, no larger than a grain of rice, belonged to a child who lived between 50,000 and 75,000 years ago, one of three Neanderthal infants whose remains were unearthed decades ago in Sesselfelsgrotte, Germany, and only recently confirmed as belonging to our closest evolutionary relatives. Now, thanks to noninvasive virtual microanatomy, these fragile fossils are rewriting what we know about Neanderthal development. Led by Dr. Miszkiewicz from the University of Queensland and co-lead Dr. Ricardo Miguel Godinho from the University of Algarve, the study published in Royal Society Open Science reveals that Neanderthal growth patterns in early life were remarkably similar to those of modern humans—despite long-standing assumptions about their divergence. Using micro-CT scanning, the team analyzed the internal structure of both milk teeth and long bones, including the femur and humerus. The bones showed advanced structural organization, suggesting rapid fetal growth, while the teeth revealed something more intimate: deep within the dentin, researchers found interglobular dentin—mineralization defects that form when tooth development is disrupted. These defects, likely formed between the third trimester of pregnancy and the child’s second year, may be evidence of systemic stress such as vitamin D deficiency, calcium deficiency, or impaired calcium absorption—conditions still seen in vulnerable human populations today. The fact that such delicate biological signals have survived for tens of thousands of years is nothing short of extraordinary. While the remains may come from as many as three different infants—one possibly unborn—the consistency in developmental patterns across the samples strengthens the conclusion: Neanderthals, like us, experienced complex physiological challenges in infancy. This isn’t just about ancient bones; it’s about kinship. For roughly 5,000 years, Neanderthals and Homo sapiens coexisted, and now we see that their babies grew in ways startlingly akin to our own. These findings deepen our understanding of shared biology and the fragile, universal vulnerabilities of early life. As researchers call for more high-resolution studies to refine these insights, one truth stands clear: in the microscopic layers of a baby’s tooth, we find echoes of a common story—one written in bone, shaped by struggle, and ultimately, profoundly human.