It's not easy to determine the gender of clams because they offer none of the visual cues associated with many other species. There is no size difference between males and females, no difference in color and no active mating behavior for an observer to monitor. For students and scientists working with individual specimens, dissection and microscopic examination is the only reliable gender diagnostic. In aquaculture, where large numbers of the molluscs are raised, their gender is determined by closely monitoring their spawning behavior. Two methods are described here: observation and dissection.