Question. Is the fellow that came on board a human being at the zygote stage? :):
It's a tough scenario. I think it would be immoral to cast the person overboard. I wouldn't owe him a ride in the boat, but it would be morally irresponsible to let him die when the risk to myself is so low. And...
Maybe he's including rape victims as being irresponsible. I kinda don't think so. So he's right as far as people having the attitude that to heck with responsibility, we'll throw caution to the wind and just get an abortion if we lose the bet.
It seems more that instead of incorrectly identifying exactly who is considering the odds over the stakes, perhaps the difference is the priority that you both assign to which odds/stakes. Again I suggest that this is an issue of worldview which determines that priority.
I agree with you that...
We had a neighbor years ago who kept complaining that she kept getting pregnant while on the pill. But she liked to get liqueured up often enough that we wondered if she took them faithfully.