This question has been posed to me many times by amateur Christians (i.e., those who do not make their living from writing about questions like this). It usually comes in a challenging tone.
Oh yeah, then why is there something rather than nothing?At least 99% of the time, the speaker seems to think that this is the first time I've ever heard such a question. To the contrary, I've heard it many times. I've never found it even a little bit compelling. I rarely bother to respond anymore. Who has time to drop whatever they're doing at the moment to teach a Christian who may not even have a basic science education about cosmology?
Maybe I'm being too harsh. The thing is, I've grown awfully tired of this same old debate and the form it inevitably takes. This isn't how science works. We don't get to rely on supernatural explanations for anything we can't fully explain. The Christian who tries this line of attack is merely revealing an utter lack of knowledge about science itself.