We all like to think that we’d be noble and put the needs of many before our own life but when it comes to the crunch…
Whilst I am still capable of living a reasonably full life and can spend it with people that I love, I would be happy to give as much blood as I could without putting my own life in danger, but not to give my life for an experiment for which the results are not guaranteed. Once I had had enough of living, say once everyone I loved was gone and I’d done everything I wanted in life, then I’d like to think that yes, I would give my life.
The next dilemma would be when someone you loved had cancer, but I think in all honesty there is only one that I would give my life for so that they could live and I suspect that they wouldn’t want that.