My Dad Questions My Sexuality

I am at work. It occurs to me that I haven't spoken to my dad in 2.5 days. So I call him during my lunch hour. We discuss menial things like the weather, our weekends, work... I mention a friend's wedding that I am attending this weekend in Seattle. Our conversation unexpectedly takes a queer turn (literally):

Me: Yeah, so I'm going to a wedding in Seattle this weekend.
Dad: You are?! As in Washington? How much was that plane ticket?!
I love how at 29 years old, my dad still asks me about my finances. In my usual fashion, I knock off about 30% of the actual cost.
Me: About $400. It'll be a bit expensive, but I'm excited. I've never been to Seattle.
Dad: That's great, I want you to experience new things.
Me: Yeah, I'm sharing a room with two of my guy friends.
Dad: Tina, are you gay?
Me: ...
Dad: Oh, f--k, I'm sorry. But you have all these guy friends. And you go camping. But you don't have a boyfriend.
Me: ...um... (wondering how I can address this in close quarters with coworkers nearby)
Dad: Tina, if you are gay, it's really OK. I don't mind!
Me: Dad, I'm not. (whispering) I like boys. I'm not attracted to girls!
Dad: I don't mean to be offensive!
Me: I know you don't, and I love you. But, um... I'm honestly a little hurt that you asked me that... are you being serious?
Dad: Well! It's crossed my mind... but I guess you are more hetero than homo.
Me: ...
Dad: I'm sorry, really, I'm sorry. I shouldn't have asked.
Me: It's OK, it's kind of funny... I mean, I do want to have a husband, and a child...
Dad: When?
Me: ...um...
Dad: So you're not gay?
Me: No, I'm not.