(The first thing that went through my mind was, how do I start this post? Great question.)
My children have taught me, or retaught me, that questions are innate; the past two years have been filled with the question why.
"It's time for dinner, please come to the table."
"Because it's time to eat."
"Because we're hungry."
"Because our bodies need calories to live."
"Because that's the way God made us."
The last phrase is used at the end of many "why" sessions. However, I do believe it's important to answer as fully as possible any question my children ask. Why? Because they really do want to know the answer, and they're learning language every time they hear their mom and I talk.
It's infuriating at 9:30pm, when bedtime is past and taunting us, to answer so many questions - especially in stereo - but we do our best. People look at us with big eyes when our 4 year old uses words like actually and perhaps (correctly), but when a child is simply talked to and his questions are taken seriously, his sponge is filled to overflowing.
And the more those questions are answered, the more likely they won't stop (sigh). In fact, they double.
If the questions stop, the learning stops. Curiosity fuels learning, and the fruit of curiosity is revealed through questions. Many of my 7th grade students aren't curious anymore; learning has become a sort of job, and school is a social club. Yet the few who have had their questions answered - and you can see it in their eyes when I answer their questions during class - continue to ask because they have tasted learning, and it tastes good.
Don't shoot a child's why down or try to stop it, answer it plainly; if you ignore the why, or refuse to answer, you'll find yourself wondering why (!) it stopped when they are adolescents or adults.
And you: keep asking! About everything!