YOUR faith tells you he is god. Since you accept faith, you do not need a reason, which is probably why you've provided no logical argument to back your claim.

How can you use a storybook as your proof? Why that one, and not the stories by the brothers Grimm, or the texts of the latter day saints?

Actually, the bible was written to match the old prophesies, and the only proof that he was born in Bethlehem of a virgin is the current version of the bible, so not much of a proof. There are versions that were discarded that said that he was born in Jerusalem. And doesn't it seem weird to you that you would have to go to your ancestor's town to be counted? That's just a crazy story put in to match the prophesies. Everything else you say is unsubstantiated.

People have written extensive treaties about it. But if no one has written anything saying that the Fairytales of the brothers Grimm are not true, does it make them more credible?

This has been measured, it's not a matter of opinion. See for example the references in "The God Delusion" by Richard Dawkins (2006).

And from personal experience (I did my phd at MIT and am doing a postdoc at Harvard) there are very religious people doing graduate studies here, but they are about 10% (in my measure), and about 30% mildly religious people (in my measure), far less than the proportion of religious people in the general population.

The "natural" argument is just nonsense. Rape and murder are natural, so we should decide for ourselves what is best, not base our decisions on what has happened before. Slavery seemed natural until it was abolished.

But if you want to go there, homosexuality is natural, it happens in most animal species.

Since it's a non-scientific claim, it's hard to argue in general. The obvious response is: what is the testable prediction? The current scientific theories are there because they are based on data and have survived the test of their predictions. What experiment would falsify the god hypothesis?

So you have to justify calling it creation.

There is no logic in such arguments, have you looked at them carefully?

So far, the alternatives require modifications (like using viruses as vehicles) that can reduce their medical utility.
As to the argument that using them supports abortion, is like saying using spare parts from junkyards supports accidents.