When there are so many highly educated and trained doctors that overwhelmingly support medically attended births and the use of vaccines, how do any of us (even with 5 years of research still 5+ years behind any doctor) come to the decision to trust our own opinion over an educated medical one.
That's just it though, faith doesn't depend on 'proof' or 'fact' so I don't think you'll find the answer you're looking for iykwim
faith
noun

1. confidence or trust in a person or thing: faith in another's ability.

2. belief that is not based on proof: He had faith that the hypothesis would be substantiated by fact.

3. belief in God or in the doctrines or teachings of religion: the firm faith of the Pilgrims.

4. belief in anything, as a code of ethics, standards of merit, etc.: to be of the same faith with someone concerning honesty.

5. a system of religious belief: the Christian faith; the Jewish faith.