Women tend to react much more negatively than men so start with your dad. Tell him that Peter Thiel is a member of an organization that you want to join because you think that the organization has a chance at greatly extending your life. If your parents won't agree to cryonics then at least get a whole life insurance policy. This will protect you against the risk that you will get sick and not be able to buy life insurance.
You might want to tell your parents that you greatly fear death, and signing up for cryonics would reduce this fear and so give you a happier life. Also, consider telling them that you will keep your cryonics membership a secret if they think this would be best. Tell your parents that you know other people who have signed up for cryonics and so if it works you won't be alone when revived. Finally, if there is something your parents really want you to do but you resist, offer a trade.
"Normal" people think cryonics is crazy, so expect your parents to think this as well. You will probably never succeed in convincing them that cryonics is worth the money and if your mom finds cryonics disgusting you will likely never get her to change her mind about this. Focus on getting your parents to let you do something that they think is a bad idea because you have earned the right to decide for yourself.
I'm not sure about donating organs if you just have your brain preserved, but I think the answer is no. If this bothers you then donate a few hundred dollars to some efficient charity and you will probably do a greater amount of expected good than if you agreed to be an organ donor.
My father is a science professor who also teaches a class on nanotechnology in literature, so he's read enough sci-fi to have a strong negative first impression of cryonics. He estimates the chance of waking up in a future that one would rather die than exist in to be higher than waking up in a more pleasant future. (I asked him a few weeks ago what he thought of cryonics, w/o mentioning personal opinions.)
I'm bad at modeling humans as compared to the general population, but I think he'd be the greater obstacle.
Also, what sort of disgust reaction to cryoni...
This is the public group rationality diary for November 16-30.
Thanks to cata for starting the Group Rationality Diary posts, and to commenters for participating.
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