How do we define a "new" species.

Atheists and evolutionists are two different things. Everybody's DNA is different. Don't you watch CSI? That's how they can catch rapists and stuff from DNA. It's like a fingerprint. Well, no, they don't. If they had the same DNA, they'd look the same as those animals. The only organisms that have identical DNA are identical twins. Right and wrong. The majority of our DNA is the same as that of other apes, like chimpanzees, our closest relative. (Chimps are not monkeys, BTW. Monkeys have tails.) In places, however, our DNA is different, which is why we're not all chimps. Well, since we stimulate the formation of new species all the time in the lab; and since we observe it all the time in the wild, I'd say you were wrong about that.

I'm curious what leads you to believe this is the case. I'm not familiar with any experiments that resulted in monkey-human hybrids. (maybe you meant "ape"? Like, gorillas? I'm not familiar with any human-gorilla hybrids either.)

That's good but it seems to me that DNA incompatibility is usually the last step on the road of speciation, and it's the step that takes the longest. But I think you're on the right track in referring to the isolation of the gene pool.In practice I think "species" tends to refer to a gene pool that is isolated now, for whatever reason, and in all likelyhood will continue to be isolated. To the degree that this relies on our ability to prognosticate about the future of a gene pool it might not be pretty, but I certainly think its the most practical, and provides the results closest to the traditional "folk" concept of species.