Some traits do not simply come from the deep family tree. They trace back to a single parent or grandparent, shaped by how genes get passed along and, sometimes, by patterns that have nothing to do with tradition or coincidence. Here is what current understanding says about where these familiar features actually come from, and where the science is still working things out.
Hair Color and the White Forelock
Natural hair color usually follows patterns passed down through both parents, with pigment genes often echoing a grandparent more than either mom or dad directly. Most variation in shade, from deep brown to red to blonde, comes from ordinary combinations of these genes. Occasionally, a baby is born with a distinct patch of white hair at the front hairline, called a white forelock. This is usually a sign of poliosis, a localized absence of pigment in the hair. Poliosis can appear on its own, but it is also one of the visible markers of Waardenburg syndrome, a genetic condition estimated to affect roughly 1 in 40,000 people. Waardenburg syndrome can involve differences in eye color, sometimes pale or two different colored eyes, and in some cases hearing differences from birth. It is inherited, and a clinician is the right person to evaluate any specific case.