Recently Thailand put a temporary ban on castrations for youngsters. Apparently a large number of ladyboy wanna be's have taken this path to avoid spending a lot of money on hair removal and other male characteristics. Sort of taking a short cut to full womanhood.
Castration basically involves the removal of the testicles (the balls). Historically, in China for example, men who were castrated became eunuchs and held important positions in an emperor's chamber.
Removal of the testicles causes the human body to produce less hair, the desire for sex and some other male traits. It is not the removal of the penis. That comes with a complete SRS, sexual realignment surgery or sex change operation.
However the potential ladyboys forget one thing - a growing number of ladyboy customers wish to be screwed - not possible if they've been castrated!
For more on castration take a look here