Attempting to determine whether a reptile is male or female, in a process known as sexing, can be somewhat difficult, as reptiles lack many of the obvious external secondary sex characteristics that birds and mammals have. Not only do iguanas, both male and female, have internal sex organs, but they do not exhibit sex differences that can easily be observed. Depending on the type of iguana and the geographic area from which it comes, males and females may be practically indistinguishable at first glance.
Look at the underside of your iguana's thigh. Males have large, distinctive femoral pores that contain waxy plugs. Females on the other hand have smaller, non-protruding pores which are often difficult to see and are not filled with a waxy substance.
Look for fat deposits behind the iguana's eyes. Males have large fat deposits on the back of their heads, while females lack these fleshy, protruding deposits. Observe the shape of the iguana's head and the size of its cheek scales, ... more.