The adrenal glands change size throughout life. The adrenal glands, lying right above the kidneys, are responsible for releasing stress hormones like cortisol and adrenaline. In the seventh month of a fetus' development, the glands are roughly the same size as the kidneys. At birth, the glands have shrunk slightly and will continue to do so throughout life. In fact, by the time a person reaches old age, the glands are so small they can hardly be seen.