Evil is not the contradiction to Theism the A-Theists make it. The presence of evil in the world (via the human heart) necessitates a Divine Presence. At the very least, the fact man recognizes evil as separate and apart from good insists on some Moral Authority.
The self-promoting A-Theistic argument that there are no Christian children or Moslem children or Buddhist children (though many moderns try to morph Eastern Mystical Religion into a meditative lifestyle, sans God, and so other than religion), only those born in the area where a certain religion is predominant is apparently meant to be a conversation ender. This is laughable. If one meets a Westerner converted to Islam, the a priori argument is rendered invalid. Reports of hundreds of thousands of Asian Moslems converting to Christianity at great personal risk is a conversation starter but not one the A-Theists can answer.
In fact, any follow-up question seems to leave the leading A-Theists floundering. These are not always serious persons.
For instance, modern A-Theists have the Devil's own time describing evil, let alone defining evil. When one's argument starts with the notion that there is no morality, no purpose, no basis for ethics, the problem of good/evil becomes insuperable. Tellingly, the A-Theists do not offer any suggestions for personal life from their own artificial view of good/evil (How could they?). They only seek to attack Theism for its ancient, time proven assertions on the subject.
When asked to interpret the problem of evil and human suffering, the A-Theist answer is to blame all human suffering on Theism, without any mitigation, though the answer the fellow gives is one he cannot possibly hold, if he is to remain consistent with his initial argument. He must then begin to add qualifiers to his argument, i.e., God (Theos) can only be good (exist) if God eliminates all suffering/evil, regardless of what good (mercy) might also be eliminated in the action, so long as this does not interfere with human free will.
You see where we are going. God is now constrained to appear at noon, garbed in white, one hundred feet tall, suspended in mid-air, call us all by our full name and spit-curl our cow lick. She may do this only by permission and, in the absence of a cow-lick, should perform emergency Rogaine administration instead.
The A-Theist must either ignore the presence of evil/suffering or accept that evil/suffering is justifiable at some level. For the Christian Realist, the Passion of the Christ is the supreme example of evil/suffering and God's response to evil/suffering. God does not ignore human suffering/evil. The only practical antidote to human suffering/evil does not involve our joining hands around the global campfire to sing Kum-Bi-Yah. God's universal, eternal answer to evil/suffering is to practice enormous, unmerited Self Sacrifice. The next time an A-Theist asks why it is God does not act against human evil/suffering be certain to advise him in this way: God's Son, God's Self, moved against human evil/suffering at great personal cost. Until you do the same, there is very little left to say.
Opinions expressed here are mine alone.