Galaxy : Maybe I'm confused? I'm not sure anymore if you mean that HRT does not cause fat redistribution. I'm 100% certain that HRT caused me to get a bigger butt and thighs, as I was 32 years old with no sign of either developing until a few months into taking estrogen. I meant "genetics" in the sense that HRT will only trigger the expression of the "female" side of your genes, the same way testosterone causes trans women to develop masculine traits in the first puberty. Someone who comes from a family of cis women who aren't curvy probably won't end up super curvy on HRT either, but even someone with the genetics to be curvy as a woman needs the HRT to trigger that female fat pattern.
It's definitely not a myth that HRT can trigger fat redistribution. Heck, I weigh slightly less now than I did pre-HRT, and I've got wicked curves after six years.