I looked at this book, The No Nonsense Guide to Sexual Diversity, by Vanessa Baird, in the university library recently. It deals with eunuchism only briefly, but has some interesting stuff in it, including a section on a genetic abnormality found in the Dominican Republic, in which the sex organs of male children, outwardly resemble the female vulva, until puberty. The book was published in England, and may be hard to find elsewhere.