Not that it happened during a job interview, but rather at group function. My direct boss out and out asked me if I was pregnant, three times. My only response to him was "I'm not obligated to answer that question." Seems as neutral an answer as anything.
Second boss in my career to do that. The first one stammered a bit when I pointed out that either A) a discriminatory question based on gender and I could take it to HR or B) I could witness him ask the same question to my male counter parts. He opted for B), and never did live it down (as they would weekly report in to him that they were still NOT pregnant).
Tara