The anthropic principle exists in a number of forms, which address the question of why the universe exists in a form which allows the development of complex organisms capable of self awareness (ie us), rather than being for example too chaotic or too stagnant.
Some forms of the anthropic principle are on a par with creationism, which tends to make some people react emotively to the issue itself. I don't think this is fair, and I think there is an interesting philosophical question which we can ask ourselves, on a par with the question 'why is there something rather than nothing?'
I do not think that the response 'because if the Universe did not allow life to form, then we would not be here to ask the question' is good enough. The best repost I read to this was someone (can't remember who) who said, if we were saved from certain death by a series of billion-to-one coincidences we would seek a reason, even though without these coincidences we would not be there to wonder at them.
Nor do I think that we must invoke the existence of god, in any traditional form, to deal with the issue.
I do have an opinion on the anthropic theory. I am cautiously confident that when everything shakes down, this is the result which will be generally accepted. I'm going to express it in metaphorical terms, so bear with those, please. (NB reading back through the following I am very unhappy with it, but I can't make it any better).
I think that an unobserved universe exists in a different form to an observed one. It exists as an expanding cloud of possibility, which is never decided, never 'collapsed' into a definite form. At some point this web of possibility includes the possibility of a conscious observing subject. At this point the observer, in the act of observation, collapses the possibilities down. Somewhat like when you bite into a foam of candy floss, and it turns into red jam.
Of necessity this 'collapse' results in a universe where the laws support the existence of this conscious observer.
I also have a hunch that the conscious observer must also influence the observed thing to some extent. That is, consciousness must exist with free will, which alters the universe as it collapses it. Thus we create the universe through which we pass, and we shepherd consciousness through the Universe that we create.
I wonder whether this collapse happened once only, at the point in the universe when the first entity came into existence, and looked about it, and that we live in the aftermath of this once-and-for-all collapse: or whether it happens every instant that we live, and perhaps through all the possible universes where entities may live. My hunch is the latter.