Actually, there are biological differences in the brain as well. Researchers have performed brain scans of transgender people and discovered that the brains of transgender men were more similar to the brains of people born with male reproductive organs than people born with female reproductive organs. It’s much more than just a “deep longing towards the other gender”. It’s science-based.
But regardless, according to the Tzitz Eliezer, once a person has the surgery, they are now considered the gender that they switched to, not the gender they were born as. Which would also speak to your point, coffee addict. Once their “private parts” change, the definition of who they are also changes. (And regarding “tell that to Hashem”– guess what, Hashem is the one who created their brains and bodies differently in the first place. Also, I don’t think by goyim it matters at all.)
It is also never a good idea to have a conversation with a gay person to “point out that perhaps they are mistaken and marriage is of opposite genders.” They aren’t going to scratch their head and say, “Oh, you’re right, so silly of me!” They’re going to go ahead and marry their same-gender partner anyway. All you will have accomplished is to contribute some pain and suffering to them and to make a tremendous Chillul Hashem in the process.
And, yes, climate change is an observable scientific fact. Got any questions?