Someone I know brought up a good question and I'd like the opinion of others on this. Is it OK for a new assistant professor (in the math dept.) to date a PhD student in another department (in this case Biology department.) I see nothing wrong since there'll never be a conflict of interest at all. I guess maybe it might look bad that faculty are dating any kind of student at all, but in this case it's a PhD student so I think it's different. What's your opinion?