"Down on Luck" joke

A young lady in the maternity ward, just prior to labor, is asked by the midwife if she would like her husband to be present at the birth.
"I'm afraid I don't have a husband", she replies.
"O.K. do you have a boyfriend?", asks the Midwife.
"No, no boyfriend either."
"Do you have a partner then?"
"No, I'm unattached, I'll be having the baby on my own."
After the birth the midwife again speaks to the young woman.
"You have a healthy bouncing baby girl, but I must warn you before you see her that the baby is black."
"Well," replies the girl. "I was very down on my luck, with no money and nowhere to live, and so I accepted a job in a Porno movie. The lead man was black."
"Oh, I'm very sorry," says the midwife, "that's really none of my business and I'm sorry that I have to ask you these awkward questions but I must also tell you that the baby has blonde hair."
"Well yes," the girl again replies, "you see I desperately needed the money and there was this Swedish guy also involved in the movie, what else could I do?"
"Oh, I'm sorry," the midwife repeats, "that's really none of my business and I hate to pry further but your baby has slanted eyes."
"Well yes," continues the girl, "I was incredibly hard up and there was a Chinese man also in the movie, I really had no choice."
At this the midwife again apologizes collects the baby and presents her to the girl, who immediately proceeds to give the baby a slap on the rear. The baby starts crying and the mother exclaims, "Well thank God for that!"
"What do you mean?!" says the midwife, shocked.
"Well," says the girl extremely relieved, "I had this horrible feeling that she was going to bark."