I have to ask _everyone_ of even remotely possible childbearing age if they are pregnant before they can stay in the x-ray room with their family member. I always phrase it "Is there any chance you could be expecting?" and 99 out of 100 respond "God NO!!!!!!!!!!" :-)

One time, I asked a coworker if she was pregnant. She was divorced, dating a relatively new guy. "God NO!!" she says, and I am horrified, because I was so sure- she just had that look. I vowed never to ask that question again. But a couple weeks later- she breaks the news- she _is_, in fact, pregnant, just hadn't known when I'd asked...