If I may, I'd like to tell you about an experience of mine:
A student (over twenty years ago) brought a box of tissues to a 'show and tell' type exercise we were doing - she had (and still has) CF. I didn't know about it, and was truly shocked. At that time, CF sufferers were not expected to live past 21.
I can't remember how long ago it was, it was at the time when Prince Philip was hospitalised at Papworth, but anyway, around that time she was able to have a lung transplant.
Without it, she would have died - she was so ill, she was permanently in hospital, in a vibrating jacket to help her bring up her secretions.
I'd always wanted to be an organ donor, but was a bit squeamish about certain things, like my corneas.
Hearing her story really made me think about it. She has been able to live a full life and is still quite healthy.
I have children. Would I want them to be able to receive organs? Absolutely (and one of my dcs may need a kidney in the future).
Your choice is absolutely your right, but knowing what I know, I've decided to put my own aversion to one side, and my family know I want to donate anything that might be useful to someone else.
Sorry my post is so long. 