Just my opinion:
I think it's somewhat analogous to discussing sexuality and reproduction with a child.1 It's best not to overload the person with information or arguments. If he/she asks a simple question or make a simple statement, the appropriate response is fairly brief and limited. The difficulty is in not trying to tell him/her more than he/she is ready to hear.
However, I doubt that there's any such thing as talking to someone about their religious convictions or affiliation in such a way as to control their response.
Perhaps the best operating principle is easy does it.
- That is, if a young child asks you where babies come from, it's inadvisable to launch into a long disquisition about the wide range of sexual practices from bondage and discipline to Monica Lewinsky's career strategy. Maybe you say that babies grow inside the mother and come out when they're big enough. You would probably do well to hold off on the egg and the sperm, until the next time he/she asks you a leading question.2
- I've got some nerve, dispensing advice about sex education for young children. I can't believe where this comparison took me!
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