birth defect
No anon, the chromosomes are XY, the regular development is into a penis and being male, it would be a birth defect for an XY individual to be born with a vagina, SRS is thus causing a defect in a male.
ego-dystonia
So a psychological abnormality in the psyche of an individual who would normally not develop an aversion to a part of their body
If you try to ground "true" transness to either a genital or dysphoric basis, you just circle back to mental illness which is exactly what the chuds argue, and it is mighty ironic that you would say we're the transphobes when we're trying to normalize it as self-id and personal adhesion to gender norms in their entirety or just a part of them, but be my guest if you want to turn SRS from a voluntary functional and cosmetic procedure to a figurative extensive circumcision necessary to enter the trans folk