well, as long as you speak of potential, i think i'll speak of potential. every sperm cell has the potential for fertilizing an egg. i, as a male, have wasted quite a bunch of sperm cells in my life. but then again, wouldn't you rather have them wasted than have me use the full potential of all my sperm cells? if i fertilized an egg cell for every sperm cell i have ever produced, the world would be swamped with humans. and i'm only 15 and 359 days, so that's saying something.
personally, i do not know where life begins. sometimes i just go along with the ideals of the regressive party (refer to: http://maddox.xmission.com/c.cgi?u=regressive)
on a more serious note, i am pro choice because i cannot condemn people for making their own minds up on having children. it's not like unborn children are actually developed, so i cannot call it murder.