But the cost of the gonads — the orange tongues found inside an urchin — is steep. Just one 200-gram box of premium gonads can cost $100. In Japan, some sea urchins can sell for five times that.

The germ cells reside in specialized environments provided by the gonads, or sex organs. Within the gonads, the germ cells proliferate by mitosis until they receive the right signals to enter meiosis.

When describing the diversity of human sexual traits, some biologists refer to the “3Gs”: genes, gonads, and genitals, said Meredith Reiches, a founding member of the Harvard GenderSci Lab.

In addition to the digestive system, the interior of the test also houses the gonads (go) and the water vascular system (rwv). In regular echinoids there are five gonads, each connected to the ...