The conceptual design of object-oriented software is difficult to learn and perform yet has a crucial impact on subsequent downstream software development. In an attempt to support the human designer during conceptual object-oriented software design, a multi-objective genetic algorithm has been developed to search and explore the design space. Two case studies are investigated using class cohesion and size as multi-objective fitness functions, and the generated solutions are compared with those from manual designs. While cohesion values are broadly similar, the genetic algorithm also produces a variety of interesting design variants of equivalent fitness that have not been identified by...