If your iguana is still a juvenile then it is possibly a male. If it is an adult then I would say it was a female. Males and females both have femoral glands. The males are usually much larger and will secrete fluids during mating season. Another way to tell is by the scales under the "ears", if the scale is VERY large and sticks out, then it is a male. Males also have larger dorsal crests(spikes) and grow larger. Females top out at about 41/2'.
