An Englishwoman and her young son were travelling in a taxi in New York. As they were driving through a rather seedy looking part of town, the boy became fascinated by the garishly made up women in short skirts and high heels who seemed to be accosting some of the men passing by.

"Mummy" the boy asked, "what are those ladies doing?"

The mother, clearly embarassed by the question, replied: "I expect they're lost and are asking people for directions"

The taxi driver overhead this and interrupted: "why not tell me boy the truth, those women are prostitutes."

The mother blushed more brightly at this remark but the boy wouldn't let it go:

"What are prostitutes Mummy, are they like other women, do they have children too?"

"Of course" the mother replied, "that's where New York taxi drivers come from."