Testes

The sperm from male humans originates in the seminiferous tubules which are located in the testes.

His research has produced proteomics maps for each species of fish he studies, showing all the proteins expressed in a given endocrine tissue (e.g., liver, adrenal gland, testes, ovary).

Slugs, like snails, are hermaphroditic mollusks, who thus have both ovaries and testes.

Sperm are produced in the testes.

In more recent times it is recorded that among the London costermongers of the Victorian age a common oath, probably misunderstood or not understood at all, was, So help me testes!