Concerning an Esper/Human Crossbreed
 

Considering how in real life, when you crossbreed two different species, there are only a few possibilities (in order from common to rarest):

1) It doesn't work
2) The infant dies before birth
3) The infant dies shortly after birth
4) The new species is infertile (Think mules and ligers)
5) The new species works (I haven't heard of this one ever happening)

And considering how for much of Final Fantasy 6, Terra is concerned with how she doesn't know what love is...

Shouldn't Terra be infertile?

Infertile women can't love?

Also, the espers were originally humans who were transformed through magic, so the genes are probably close enough to be okay. I'd be willing to just credit it as mostly magic, though.

I never said infertile women can't love, I just said that love is a pretty big theme for her. Which I thought was kind of ironic, considering the... well, the common end result.

And I never knew about the esper/human relationship, but I'm suspicious about that considering how many espers are just cute forest critters. Also, Bismark? He's a giant whale. Doesn't seem like a magical human to me.

Magic would explain how Terra survived. But it doesn't necessarily mean that you could end up with a quarter-esper child.

Well, aside from it being stated on the little statues in the cave near Thamasa, let's allow Wikipedia to explain:

So yeah, magically-transformed humans. And Maduin being among the most humanoid of all. It's not out of the realm of possibility that the DNA was compatible. Also, magic can kinda mean anything. It's magic.

Also, in the case of something like the liger, only the males are infertile. The females often are fertile.

You see, the division of species isn't quite as clear cut as the traditional definition says. Hybrids wouldn't be possible at all otherwise.

I believe I've heard of a species of wolf that was actually a viable hybrid of two other species.

Proof that rule of 34 never applies to NPF, cause only on NPF will we discuss the mating habits of video game creatures without it turing to hentai

http://i119.photobucket.com/albums/o.../facepalm4.jpg

He has a point.

Ramuh/Shiva were more humanoid. Ramuh was an old dude with a beard and shiva was just a blue chick.

And to answer your question, magic allows Kefka to shoot giant laser beams that are both capable of ripping apart a continent AND incapable of incinerating heroes. I imagine it can laugh at some laws of biology while mocking the laws of physics.

Just to end this derailment before it gets a chance to begin, there is NPF-related porn out there and, no, you may not see it.

Anyway, yeah, it's unlikely that Terra would have been infertile given the magical elements surrounding the creation of espers as a whole, and that it was less a matter of DNA and more metaphysical transformation. Also:
I said "among the most humanoid", emphasizing the key word here.