Largely true. The Ottoman Turks and Arabs (and Greeks and others) would castrate SOME slaves--for instance, those that worked in the harem--but not necessarily soldiers, administrators, other servants, etc.

What's really interesting is the Ottomans and Greeks got in an argument over the best way to castrate. The Ottomans would cut it all out--root and stem, no cock, no balls. The Greeks would usually leave the cock. Turks viewed this as immoral and debauched, because apparently the eunuchs could (and would) fuck to some degree.

Cutting it all off removed any chance of harem hankpy panky -- at least from the eunuchs. Certain vegetables WERE forbidden...