The list you mention is not very strong evidence that "people are born with their sexuality". It's a list of correlations of varying quality and effect size that is subject to strong publication bias. More importantly, all of these correlations are perfectly compatible with the possibility that genetic/prenatal factors only partially influence one's sexual orientation rather than completely determine it.
Please read the section on twin studies that opens the Wiki page you referenced. The epidemiological twin studies are probably the strongest evidence we currently have, and they suggest that genetic factors play a role but do not determine sexual orientation.
Thank you, I was not expecting that. It is time to update my beliefs. I knew I had lots that were not based on proper evidence gathering, but I was not expecting such strongly held beliefs to be so easily falsifiable. It would appear I have a ways to go. On the upside I at least now have an intuitive understanding of how being wrong feels exactly like being right whereas before I only had an intellectual understanding. I suspect I shall have to beat myself about the head with that memory
I'm trying to figure out what this implies for the gay/trans rights mo...
What is something you used to believe, preferably something concrete with direct or implied predictions, that you now know was dead wrong. Was your belief rational given what you knew and could know back then, or was it irrational, and why?
Edit: I feel like some of these are getting a bit glib and political. Please try to explain what false assumptions or biases were underlying your beliefs - be introspective - this is LW after all.