I always had doubts about things like a brain dead person ending up in heaven with their brain working perfectly (with no body to support it). What really got me questioning though was at a time when I was trying to strengthen my faith. I was striving for perfection in my "walk with God". I was going through a divorce, and my kids were staying at my house with my ex, while I was living apart from them. Naturally I worried about them, so I prayed every day for God to take care of them when I wasn't with them.
At the time, I was reading the Bible daily, and believing it. I especially remember John 15:7- King James Version
If ye abide in me, and my words abide in you, ye shall ask what ye will, and it shall be done unto you. I really believed God would protect my kids when I couldn't be there. To make a long story shorter, my ex-wife had a horrible car accident and my 10 year old son was killed.
I didn't get mad at God even though I was still a believer. In fact I thanked God for being with me during all of that. It wasn't until later when I reread that verse that I realized either God was a liar, or what I had been taught about the Bible being the word of God was wrong. I chose to believe that God wasn't a liar, it was just that the Bible was flawed. From that point on, it didn't take long for my whole belief system to unravel.
I'm still amazed it was that verse and not all the thousands of other unbelievable things in the book that started me on my journey out, but that's what started it.

For me it was the Adam and Eve story. It is completely preposterous. As a Catholic, it is a sin to be born and you have to be baptised to free you from Adam's sin of eating the stupid fruit from the tree. OK, so dump that and just go with Jesus. But, why did Jesus have to die? Because Adam and Eve ate the fruit and were kicked out of paradise. So it all goes back to that? It all went downhill from that. None of it makes any sense, it is ALL preposterous. It reads like mythology. The conclusion is, it IS mythology.

Nope, I just never had any faith. I learnt about god and Jesus just as I did the tooth fairy and Santa Claus, and then without proof they disappeared from my logical (ish) adult world
But as an adult I do find the impossible standards set by the virgin birth quite offensive.

The doctrine of Hell and this god having a plan that required "he" allow so much suffering were big ones for me. I also had problems trying to reconcile the god of the "Old Testament" with the god of the "New." They are so very different.

Hypocrisy, racism, misogyny etc I saw in church after church I attended caused me to leave organized religion.

Although I had doubts that mounted over the years, one defining moment was when I was taking Spanish at the University of Oregon. I would practice with my neighbor, who was from El Salvador. One day, I asked her how to translate something from English to Spanish; she did not know the Spanish translation (I don't even recall what that was). I had also learned about Lilith somewhere along the way.

This got me to thinking: how could we presume to think that the ancient writings in the Bible were interpreted correctly? And, what other Jewish stories were out there that were not known by Christians. I very nervously began to check out books that I knew would challenge my beliefs. I justified it by thinking that god would prefer an informed follower as opposed to blind obedience (boy was I wrong--this god demands it).

Once I started challenging my beliefs, the flood gates opened--my mind opened. My journey from leaving organized religion to becoming an atheist took about a decade. Some personal tragedies occurred along the way; but-- they did not cause my doubt--they only solidified the doubts I already had.

It was learning more science that led to my atheism.

So , in short (haha) it was intellectual doubt that spearheaded my journey.

Too many contradictions .

initially stopped believing around 12-13yo, it just was like a fairy tale, dinosaurs vs adam & eve since 9yo, I loved family, but simply didn't believe, even tho we were going to Lutheran
private school. Family life was dystopia lol. I left home as emancipated minor at 17yo, graduated HS and worked like crazy. My parents couldn't figure how I could live without believing, but I saw the opposite. After my kids were born, I wanted to give them a god of kindness, stability as a grounding and representing good in the world, one more try. But over time the way I was raised "to always turn the other cheek, and give selflessly" like a "good woman" just made myself & my kids victims. I couldn't save my kids or myself from DV. I joined church again rebound, wanted to believe that if I believed enough I could get myself and my kids out of the hell my ex had created by trying to make them fear me. Then saw the people whom I trusted bought off one by one by his sorry ass, including my churchgoing family. Everyone was bought. That confirmed my atheism, I really cannot deny the greed and manipulation behind most religious orders. I was desperate, but the brutality of not being able to save my kids or myself from despair of being isolated from them was the final lasting shock. There is no external locus of control that resembles god, spirit, or energy, this is internal locus. I find, again, that connecting is beautiful, but not imperative. We are whole when "alone", and are whole when sharing. , if that makes sense. I love the endless ways that living surprises, and cherish loved ones, life, whimsey, knowledge and challenges. Also don't know why am I'm writing this lol.

My transformation was due to intellect. I tried to prove my religion true in order to make converts. Instead, I found evidence that the prophets were false (unable to predict the future with a superhuman degree of accuracy), and the scriptures were false (full of contradictions and unscientific myths).

This is the reason that religious leaders tell their followers to believe by faith alone, and not ask questions or think skeptically, critically, scientifically or reasonably. If they do start thinking, they would leave the religion and stop paying money to the church. Religion is a scam based on mythology.

Intellectual doubt.. I remember being about 10 years old or so, starting to question all of the fairy tale type stories they were telling us in CCD. I’m like wait... how’s that possible? It made no sense to me at a very young age.

What started it for me was the hypocrisy I saw when HIV first came out. They said God sent it to get rid of the homosexuals. I asked why innocent babies and other people would catch it is that were true and was told it was just basically collateral damage. At that point I knew religion all about control because this was opposite of a loving God. Once you question one thing it starts to snowball. I now joke that if all these so called Christians are going to heaven, then send me to hell with the decent people.

The idea of a soul didn't make sense to me because energy is neither created nor destroyed so whatever all these souls are being constructed from would be constantly getting depleted since souls go on forever

I didn't "doubt" first. I REJECTED first. I rejected religious faith based on being "divinely" relegated to a second class citizen on account of my gender. Then, I rejected the entire faith forever based on religious teachings against homosexuals. I remember telling someone "If God rejects my friend Greg because he is gay, then God is wrong." It kind of went on from there. The more I learned, the more I was able to reject it based on it's teachings. I vowed never to teach, condone or demonstrate anything from "holy" texts. Lastly, and if need be I still use this "argument" ... Humans have freewill. The human men who wrote the Bible wrote it with the will to write whatever they wanted it to say. ... Then follows, "God wouldn't let that happen." He allows children to be raped, but not his word to be obscured?" Sorry, ... NO.

When I was thirteen, I was told during Sunday school that Dinosaur bones were placed by The devil to lead you away from God.
That was the last time I attended church.

I never believed. I’ve tried; it’s just not there. Each time I tried, the sheer ridiculousness of the doctrine just was glaring. So I quit trying. Now I’m fully aware of reality, and it doesn’t scare me to know there’s no sky daddy.

The "sacrament" of confession. It occurred to me at 14 that telling some guy in a dark box how many times I beat off that week or I'd go to hell if I died was a pile of horseshit. The intellectual parts came after that.

It was the realization that like all myths, somebody made it up! After 12 years of Catholic schooling, simply with an extra hour of reading and writing, even though it was about religion, made us too smart for the myth. We had physics biology, geometry and those disciplines do not match well with pure science. And that's not to mention all the classes where the Priest came around and answered questions. Juniors and Seniors were always asking probing questions, a tough audience! It was, hand in the air, Father, Father. Yes Mr Vance. What about? One would get the reply, "It's a miracle now sit down Mr. Vance!!

Years spent critically reconsidering what I had been taught. The claims and promises of religion are ridiculous when you really examine them. You just have to get past the programming not to question your faith.

I started doubting in my early teens, though I hung on for a long time. I remember thinking then that it made no sense that God would refuse entry into heaven simply because someone was of another religion, even if that person was a good human and treated others well. I just thought that was ass!!

There was a time when I was in public middle school, 11 or 12 years old, when we could get out of class to attend bible school on Fridays for an hour. During one of those classes in which the person leading the class was talking about entry into heaven being dependent on Christian belief it occurred to me that it did not make sense. I thought there must be people in the world who met the Christian criteria as one who would qualify to go to heaven but, due to the circumstance of their birth and where they lived, have never heard of the Christian God. A person living in a tribe in the Amazon jungle as an example. It was then that I came to the conclusion that if there was a Christian God - he like all Gods was a myth.

Experience was the catalyst. Generically speaking it was that my faith did not accurately explain or predict lived experience. In fact more often than not it was not just a miss, but totally wrong, 180 degrees wrong.

The Bible is full of completely contradictory claims, so maddeningly you can make a case for everything from "god helps those who help themselves" to "god wants you to be rich and successful". The teaching I received was somewhere in the middle of those two, but even so I wasn't too far into my adult life before I discovered none of the following were true:

• God blesses the righteous and confounds the wicked
• God protects his children
• God comforts his children (when, apparently, he fails to protect them)
• God conveys wisdom and insight and helps you live a "victorious" life

That's just a small sampling. All of them come with weasel-words, too. If you are "confounded", maybe you are wicked -- even if you don't think you are. Secret sin, insufficient piety, etc. Case closed. If god doesn't protect you then you're simply not a true child of his. If god doesn't comfort you perhaps he's chastising you. If god doesn't make you wise and insightful maybe you're not listening to him enough.

I hasten to add that while experience was the catalyst, once I got out of the "reality distortion field" that was my faith, I had far better reasons to reject my faith than just that it has disappointed me or failed to deliver sufficient value. Like that it's completely false and made up. That sort of trumps my original reasons for questioning it.

A two-thousand-year-old bunch of writings without ONE SHRED of evidence since.

At age 13, I became an atheist when I realized the Bible is just a book of stories written by men. Told my mother I don't want to go to church anymore.

"That's fine, honey," she replied. "I became an atheist in nursing school when I realized a woman cannot turn into salt." She laughed.

I never believed Bible stories. They were like Grimm's Fairy Tales. As a small child, I inwardly scoffed at Bible stories. Smart kid with 146 IQ (still is).

My grandparents attempts at indoctrination were feeble. At 6 or 7 I asked how could anyone know God said let there be light when no one was around to hear it. Of course I got a dishonest response, but the point is I was born a skeptic a free thinker who thrives on accurate information. Naturally the more I learned especially with origins of religion, the less I believed. I never really believed the eronious absurdities anyway.

it’s always weird to me that people use the virgin birth as an example for this. if an all-powerful being existed, one that created humans from nothing, it could absolutely make a virgin woman become pregnant. hell, it could make a cis man pregnant too, what’s stopping it?

for me, it started with the lack of logic. things like how prayer works if god is omniscient. why are pain and evil necessary for the “perfect” plan of an omniscient, omnipotent god? i never figured it out, but i put those questions to the back of my mind for a while. then when i lost my nephew, who was only three, i couldn’t stop thinking about it. i realized there would never be a reason god could give me for my nephew’s death that would satisfy me. no “plan” would make sense for an all-powerful god who could have easily just not created illness or death. i could accept that a being who created everything could also work miracles, that’s fine, but i started to see the lack of logic and finally realized it was all a fairy tale to make people feel better about being helpless.

I think once someone accept that a super powered magic entity exists then virgin birth or peaking animals are really not a problem. If miracles exists all the biblical fantastic histories are acceptable.
But see the little IF there? This is the central argument. IF it exists then you can build a whole religion/culture over it. But that if can never be solved, you just ignore it, repeat that it is true and when enough people are into it, no one will question.

The questioning of my beliefs was when I got some distance from churches because I moved out of my town. At the same time I started having more contact with scientific method and rational thinking and started to see that churches refuse to even look after their members in a systematic way.
At first I was even eager to use rational approaches to help the church, to reach further into the people, help more and spread more the gospel, working with those that had not really had a "personal meeting" instead of just showing the ones that had as a trophy.
But then I understood that to not have this approach is the point of the churches. To focus on some "enlightened" individuals and give the idea that you are one of the few that don't have this "contact with god" is the strategy.
Avoid precise information and correct assessment of the members and leave the false idea that the church is a blessed place is the strategy that keeps it running.
This point I started to question and seeing that if you put rational approach everything crumbles. I started looking for the "proofs" and all was myth, or authority based arguments, or fallacious.
Then it was natural to reject that little IF and all started being ridiculous. A whole life based on an IF that for all purposes seems to be false.