What's a good question to ask an anti- Abortion Christian protestor?

There are a couple of Christian anti Abortion protestors who hang around the centre of town most days ( they obviously have nothing better to do)

What's a good question i can ask them that they won't be able to answer back? If they try and change the topic i'll keep going back to that question.

What's a good question to ask an anti- Abortion Christian protestor?
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