Quote Originally Posted by simonj View Post
Well, as Mr. E pointed out, a dolphon or a Saint Bernard is not going to ever become a person with whatever it is you define as a large enough amount of brain function to qualify as a 'person'
a zygote has that potential. a just-fertilised egg has that potential. EVERY SPERM HAS THAT POTENTIAL. that's the problem with the "potential" argument.

Quote Originally Posted by simonj View Post
Of course there's a leap. Not many people equate sperm with actual people. That's usually associated with religious beliefs anyway.
it's a religious belief for a reason. because religious scholars correctly went "ah, hang on -- if we're against killing people because of souls, and we don't know when a soul gets there, we have to be against baby killing, even if it's in the womb, because it might have a soul, and if it doesn't, it has the potential to have one. in fact, every fertilised egg has that potential. uh oh! no abortions for us!"

if you argue from potential, you have to argue for the protection at the VERY LEAST of every fertilised egg. but then you have to rationalise away why you don't think every single sperm is sacred by saying something like "well, not everything that has the potential needs to be cultivated, but to actually get in the way of that potential is not okay".