I am sure that the author wanted to avoid situations like the following:

My sister happens to be a pediatric RN and she recalls the time she was with a young male patient and asked him if he needed to void. He said no. Since he was rather figidity, she asked him again and he looked at her oddly. So she then asked him if he needed to urinate and he once again said no. She left and just a few minutes later, his light went on. She proceeded back to his room where his mother told my sister that her son needed to go the bathroom. So my sister told the mother that she had just asked him a couple of times and he had said he didn't have to go. The mother then questioned her son, who insisted that my sister had NOT asked him if he had to "empty his teapot"!!! My sister said in all her years working with children, that was the first time she had heard that particular version. I remember my sister telling me this story and begging me to make sure when I had kids to make sure I taught them the correct names for body parts and bodily functions. I have made sure from the very start that my children were taught the correct names even though we do use "kid" words like "potty" etc. Regardless of any "special" words used within a family, I do think it wise to inform them of the "correst" terminology.Just think, if that young man hadn't been in the hospital to experience the "void" situation, he could have been a grown man always commenting that he needed to "empty his teapot"!!!  :) Still cracks me up every time I recall it!!!

Valerie