Late last week, headlines appeared suggesting that humans might have two brains, based on new research. These headlines came from a press release by one of the universities involved in the study. However, it's important to clarify that humans do not have two brains. This interpretation of the study's findings is misleading. The research does not support the idea of a second brain in humans, but it does offer valuable insights into how the brain develops and can help scientists better understand broader concepts in developmental biology. The study focuses on a key question in biology: how do the segments of the body form during development? This is a central topic in developmental biology, a field that explores how organisms begin as a single cell and, through a series of carefully timed and coordinated processes, develop into all the tissues found in adults. Understanding this process is crucial for many areas of medical and biological research. By the time the first cells committed to becoming neurons appear, the vertebrate embryo—such as a human or animal—already distinguishes its head from its tail and its back from its belly. At this stage, the embryo consists of three main layers of tissue: the endoderm, which will eventually line the digestive tract; the mesoderm, which will form muscles and bones; and the ectoderm, which will develop into the skin and nervous system. Vertebrates, including humans, have four primary segments in their developing nervous system: the forebrain, midbrain, hindbrain, and spinal cord. Some of these segments later develop additional parts, but the study focuses on how these initial segments form. This research contributes to a deeper understanding of how complex structures like the brain develop from simpler beginnings, offering valuable knowledge that could benefit medical science and biology in the future.