If your little one asks you "The Question", you can
semi-clearly utter, "Philippian tubes" and show him/her a
map of the northern-Aegean-Sea area. That way, you are giving an essentially-truthful answer, while still "keeping the conversation G-rated" --- i.e., without divulging any actual "adult-themed" info. Plus said youngster
will likely become either bored or "info-overloaded" while staring at the map, and thus
will forget about his/her original question.