A female transgender mixed martial arts fighter is now under investigation by the Florida State Boxing Commission.

Fallon Fox underwent gender reassignment surgery in 2006 along with the supplemental hormonal therapy. The 37-year-old Fox is licensed to fight women but on the license it didn't mention the surgery.   

On Saturday, Fox knocked out a woman in 39 seconds at a fight and holds an undefeated 5-0 record with all five wins coming in the first round.

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