In your opinion what causes christians to believe in Jesus

[Sheldon]

In my experience, christians believe because they think or wish (and I mean nothing untoward here, I call this genuine) that a remarkably small number of pregnant propositions are (or were) true.  Conversely, a person will not believe in christianity if they think or wish that even one of those items aren't true.  The odds aren't in the christianities' favor - which might explain why more skeptical populations are less christian by brute force of large numbers.   Why the number of people who believe in one or more, but not all, of these propositions..... is far greater than the number of christians.

Gods exist and are theistic.
Moral content exists and is objective.
Gods can modify moral desert.

-and all of this is acceptable.  

Notice "atheists have bad brain" isn't in there?  Not because it can't be true, but because it doesn't matter if it is.  We can zero out all the bad brained atheists...and we can imagine that's 99% of us...but the remaining 1% will still have a solid logical case against christian belief.  Which is to say, that even if gods exist, and even if objective moral content exists, and even if gods are personal and intervening, and even if the manner of their intervention is to modify moral desert.....that would be bad...and so, it doesn't actually matter whether or not it's true.  No more so than it matters whether or not some dipshit is in charge of a county's laws.   That's granting a hell of alot to christian belief....not just possibility, even actuality... and it still has mount improbable to climb at the very last step.  We are, or at least should be aware, that there are people in mechanically equivalent and undeniably factual circumstances who do not affirm the appropriate beliefs.

Well John's "bad brain" idea was offered, as are all his beliefs, without even the pretence of any evidence, it is a no true Scotsman fallacy. 

Rather than addressing the dearth of objective evidence for any deity, or more specifically the one version of the one deity, from the countless thousands humans have imagined, that he believes is real, John has relentlessly attacked those who don't share his belief. These attempts to reverse his burden of proof, is of course nothing new, it seems to be in vogue in apologetics, but is of course irrational at its core.