Oh, that's excellent! [Biodiversity of...what? Either way, his mother will be thrilled! Both of her children married to doctors!] I don't know what that means, but it does sound interesting. [No it doesn't, but that's okay. She found it interesting enough to get a doctorate in it. There must be something interesting there.]

I-- I mean, you can come to one of my shows if you'd like. But I'm sure it's not half as stimulating as your... [what do doctors do? Oh dear, she's probably a professor, someone's teacher. Someone really clever. What do clever professors do?] conferences?