Figure 3. Animals of mixed-sex genotypes showing both male and female sexual traits.

(A) Bilateral gynandromorph chicken. Right side has cells that are predominantly ZW, while left side cells are predominantly ZZ. Consequently, female characteristics, e.g. small wattle and small leg spur, are expressed on the bird’s right side (brown plumage) while male characteristics, e.g. large wattle, large leg spur and greater muscle mass, are expressed on the bird’s left side (gold and white plumage). Photo courtesy of Dr. Michael Clinton, The Roslin Institute, The University of Edinburgh. (B) “Vincent”, an XXY gray kangaroo (Macropus giganteus) showing both male and female characteristics. The black arrow indicates the pouch, which is determined by the number of X chromosomes, while the white arrow indicates the penis, which along with the testes is determined by the presence of a Y chromosome. Photo courtesy of Professor D.W. Cooper, University of New South Wales.