Pretty sure Planned Parenthood has nothing to do with HRT prescriptions. You'd need a psychiatric doctor to prescribe something like that, and he'd probably insist on a pretty thorough examination. And since doctors don't generally like giving out prescriptions needlessly, he'd probably want to hear about some symptoms of illness first.
Preference alone would be insufficient, just like going to your doctor and insisting you want your stomach stapled for weight loss would be insufficient to get the surgery. He will most likely make you try other, less permanent things first.