Wut? Eunuchs have been around forever. They don’t become women; just neutered men. What do you need an experiment for, Dr. Mengele?
From Britannica:
Apr 4, 2023eunuch, castrated human male. From remote antiquity, eunuchs were employed in the Middle East and in China in two main functions: as guards and servants in harems or other women’s quarters, and as chamberlains to kings.
Also in European choirs.