Joke: Logic & Flawed Reasoning

This is my all-time favorite joke ever! It was told on the Conan O'Brien show by one of the funniest men on the planet - Norm McDonald. He does a much much much better job in telling it in only the way that Norm McDonald can tell a joke, but this is the best way I can recount it. And this will be my last joke for awhile. I know it's kinda long...but I think the payoff at the end makes it worth it.

Bob had just moved in to a new neighborhood and was talking over the fence with his new neighbor for the first time. The two began discussing things that new neighbors discuss.
"So what do you do for a living?" Bob asked Richard, the new neighbor.

"I'm a professor of logic at the local University," Richard proudly responded.

"Logic? What's that?"

"Well," begins Richard, "it's probably easier if I just give you an example rather than tell you what it is."

"Okay," Bob replied inquisitively.

"Well, I see that you have a doghouse in your backyard."

"Yeah," replies Bob. "That's a doghouse."

"So I'm assuming that since you have a doghouse, you must have a dog. And since you have a dog, chances are you probably have a family."

"Okay, Richard," Bob said. "So far, you're right."

"And since you have a family," Richard continued, "that means you have a wife, and kids...am I right?"

"Yes..yes, you're right."

"And since you have a wife and kids, I deduct that you're a heterosexual. Is that correct?"

"Yes..that's correct."

"So you see," explains Richard, "just from taking the fact that you have a doghouse, I was able to deduce that you're a heterosexual."

"Wow," says Bob. "That is pretty amazing." Later that day, Bob was waiting at the bus stop with another gentleman. He strikes up a conversation with the stranger. "I was talking to my new neighbor earlier today," he begins. "Turns out, he's a logic professor at the local university."

"A logic professor?" the man says. "What's that?"

"Well," begins Bob, "let me give you an example. For instance, do you have a doghouse in your yard?"

"No," replies the stranger.

"Well, what are ya," Bob exclaims, "a homosexual??"