The synthetic androgen 17α-methyltestosterone (MT), used pan-tropically to masculinize tilapia fry for farming and sale, results in the development of intersex crocodilians by masculinizing female crocodiles and is detectable in crocodile egg yolks within natural systems, making MT one of the first environmental androgen endocrine-disrupting contaminants. Biotic and chemical exchange between aquaculture farms and human water sources are often unrestricted, leading to MT being detected in vertebrates throughout the region. The proposed research will result in a behavioral and neuroendocrine understanding of MT as an ecotoxin and its potential contribution to mechanistic human pathology post exposure.