Many diseases or disorders originate with a loss of cellular function. Cell death or damage is at the root of many problems associated with aging or injury. But what if the cells lost could simply be replaced to restore function? Brian Culley, CEO of Lineage Cell Therapeutics, discusses how his company has identified ways to generate specific cell types that can functionally replace lost cells in various contexts, restoring function. We discus applications in macular degeneration, hearing loss, and spinal cord injury, with potential applications in Type 1 diabetes, Parkinson's disease, and many future applications.