The testicles of calves, lambs, roosters, and other animals are eaten in many parts of the world, under a wide variety of euphemistic culinary names. Testicles are a by-product of the castration of young male animals raised for meat, so they were probably a late-spring seasonal specialty, though nowadays they are generally frozen and available year-round.
Testicles are cooked in a variety of ways: sautéed and sauced, fricasseed, deep-fried with breading or batter, in pies, poached, roasted, and so on. Before cooking, they are generally scalded, skinned, and soaked in cold water.
Testicles are known by a wide variety of euphemisms, including 'stones', 'mountain oysters', 'prairie oysters', and so on. Lamb testicles in particular are often called 'lamb fries' or simply fries (though that may also refer to other organ meats). The French term "animelles" is occasionally encountered. In Spanish speaking countries in Central and South America they are known as huevos de toro, or 'bull's eggs', although this is by no means a euphemism but well known slang in Spanish speaking countries. Similar to English speaking countries that refer to testicles as "balls". "Huevos de toro" could be translated as 'bull's eggs' but it is more accurate to translate it as 'bull's balls'. There would be no doubt to anyone about what "huevos de toro" are, while the translation 'bull's eggs' can be misleading to non-Spanish speakers.
Greece and Cyprus
In Greece and Cyprus, lamb testicles (Greek αμελέτητα) are often grilled on coals .
In the United States, bull testicles are usually served breaded and deep-fried as an appetizer, under the name "Rocky Mountain oysters".
Media related to testicles (meat) at Wikimedia Commons