DNA needs to replicate before cells divide to ensure that each daughter cell receives an exact copy of the genome and inherits the complete set of genetic information. Without DNA replication, the two new cells resulting from cell division would not have the full genetic instructions required for proper structure and function. DNA replication occurs during the S phase of the cell cycle, creating two identical DNA strands so that when the cell divides, each daughter cell contains identical genetic material to the parent cell. This replication process safeguards genetic continuity and stability across generations of cells and enables accurate inheritance of traits.