It's a relative thing

When you have low body fat, it's not so much that you're producing more testosterone. It's just that the testosterone you have is not being converted into estrogens.
Fat cells promote estrogen production. Fat cells are loaded with aromatase (an enzyme) and that tells fat cells to store estrogen. Testosterone is then converted into estradiol and androstenedione to estrone. The higher your percentage of body fat, the more estrogens your body will produce and the fatter you will get unless you control your diet and use supplements and exercise to lower that estrogen production.
That is why females with low body fat percentages stop menstruating. They don't produce enough female hormones to ovulate because they lack the required bodyfat to be "female".
BTW, zinc inhibits the aromatase enzyme, so if you want to lose fat, take zinc.