This document discusses cell fusion, including its definition, types, advantages, disadvantages, and methods. Cell fusion is the process where cells combine to form a multinuclear syncytium. There are two main types: homotypic fusion between identical cell types and heterotypic fusion between different cell types. Key methods to fuse cells include polyethylene glycol (PEG), electrical fusion, and Sendai virus. PEG acts to dehydrate and fuse cell membranes but can be toxic, while electrical fusion and Sendai virus are more targeted and reproducible. The advantages are its research applications, though it poses genetic stability risks.