Brainstorm

[Excited Penguin]

Because at the moment of conception a brand new set of human DNA is formed. A sperm is just a sex cell from the man's body, it isn't its own separate entity. 

Ok, I agree with that. But we're still talking about it's potential to become something more here, if you wish.

To address your last paragraph though, a human fetus begins to feel pain about midway through the second trimester... at least as far as we can tell, though it could be before that. But I don't think the ability to feel pain should be the indicator to being human. If you are comprised of human DNA, you are a biological human being, whether you have the ability to feel pain or not, imho.

(Emphasis mine.)
That may very well be true, but then humans that can experience pain take precedence over human fetuses that can't. Would you agree with that or not and why?