Taxi driver

A woman and her ten-year-old son were riding in a taxi.
It was raining and all the prostitutes were standing under the awnings.
"Mum," said the boy, "What are all those women doing?"
"They're waiting for their husbands to get off work", she replied.
The taxi driver turns round and says, "Geez lady, why don't you tell him the truth? They're hookers, boy! They have sex with men for money."
The little boy's eyes got wide and he said, "Is that true, Mum?"
His mother, glaring hard at the taxi driver, answers in the affirmative.
After a few minutes, the kid asked, "Mum, what happens to their babies?"
"Most of them become taxi drivers", she said..