"My team successfully demonstrated that while hormones do have a direct effect on the fish's physical structure (like gonads, genitalia and fins), the fish's behavior answers more to its position in the social hierarchy," he said.

So what can we Homo sapiens learn from these fish?

Researchers' efforts are showing us that two seemingly distant vertebrates actually share quite a lot of characteristics. As Grober firmly asserted, "Us IS them."

In both people and these fish, behavior answers to social context; it's only partly determined by physical sex and size. Sexual behavior in humans and gobies is malleable: It is able to change based on an individual's placement in the social hierarchy.

Grober argues: We should not think of fish as being like robots or automatons, because they make complex decisions regarding reproduction just as humans and other social animals.