Science actually pretty much reached the concensus that: yes they can.

Because these people still mistake sex with gender… but they like to quote outliers to make it seem like it's a MAJOR ongoing discussion, the same way they quote outliers that deny vaccinations or climate change to make it look like they are ongoing discussions and hadn't been settled decades ago.

Especially since up to 1% of people can have genitalia and other body deformations that make them look like they are of the other sex… and that is the one they identify as they grew up under that presumption, even if they are genetically the opposite. Surgical reconstruction generally fucks them over mentally. Because for them that is an unconsensual sexual transition. (W. G. Reiner and J. P. Gearhart N. Engl. J. Med. 350, 333–341; 2004).

Politicians try to craft laws to FORCE scientists to see gender and sex as the same thing which would retroactively "make them right"… since they just changed the definition of words.

And in the same way science is discovering the purpose of homosexuality, they are also researching if transgender serves a biological and evolutional function in some way. (In Homosexuality's case: homosexual penguin couples often adopt orphaned chicks, because heterosexual couples are busy raising their own offspring. Without gay penguins they'd all starve and none would get a second lease on life, even if their genes make the species fitter).

"Changing Gender is a rather normal thing"
I wouldn't call it normal when less than 1% of the population does it.