Wireless Mobile ad hoc network is a collection of independent mobile nodes that can communicate to each other via radio waves. The mobile nodes that are in radio range of each other can directly communicate whereas the others need the aid of intermediate nodes to route their packets. These networks are fully distributed and can work at any place without the help of the infrastructure. The topology of the network may change unpredictably and frequently. Therefore, multicast routing in ad hoc networks is a very challenging problem. This paper proposes an Encoding method, Fitness Function, Genetic Operators which can be used to solve the multicast routing problem.