My husband and I are currently in marriage counseling. Of course my BDSM interests came up and the counselor clearly stated that my interest in that is considered a "mental disease" and even stated what the clinical term for it was. I can't remember the clinical term at the moment but will search later and see if I can find it. (Love you guys but would REALLY rather not ask the counselor again and bring THAT entire discussion back up...)
So... not sure how to approach Dear Old Dad... but it is, from my understanding, taught as a mental illness. Which I find is truly ironic since most who go to counseling are there to "find themselves" or "better themselves" and how is that possible if you are being told that what you feel is wrong for whatever societal contrived reason.