Are the laws of nature set in concrete?

Is it possible in our 'sophisticated and enlightened' 21st century to believe in a virgin birth, i.e. a miraculous birth? The issue is very important for Christianity, the only major religion that depends on miracles. Saint Paul, in his first letter to the Christians in Corinth, wrote that if Christ had not risen from the dead, both his preaching and their faith would be "useless". Many moderns disbelieve that Christ walked on water, quietened a storm, fed a multitude with just a few loaves of bread and a few fishes, and brought back to life a chap whose body had been in the early stages of decomposition.

According to atheist Richard Dawkins, the miracles Christians believe in are "blatant intrusions into scientific territory", and that every one of the abovementioned miracles amounts to "a violation of the normal running of the natural world"; "bad science", so to speak.

In 1835, David Strauss published various 'explanations' for the miracles: perhaps Jesus had a secret store of food, or people had brought their own packed lunches; perhaps there had been a platform under the water's surface when Jesus walked on it. And Lazarus? Well, he might have been in a trance. Very predictable stuff!

We know that all medical attempts to bring a dead person back to life have failed. It does not follow from the latter, though, that a dead person returning to life would constitute a violation of the 'laws of nature': miracles can be seen as actual suspensions of natural laws.

Can anyone claim with a ring of confidence that the laws of nature are immutable? Are set in concrete?