Kane said:
No. Not true. Superman's DNA is vastly different, he may not have powers on Krypton but his DNA is different enough to allow him to gain abilities under the red sun.
Hes an alien. His appearance may be similar to earth men (as are alot of aliens on shows like Star Trek) but his internal chemistry is waaaay different.
I think they should be able to have a kid eventually by the end of the franchaise but they shouldnt be able to have one natually (I dont think theyll be able to have one naturally in the comics either) with the Kryptonian and Human DNA being different.... but a doctor or some scientist will find a way to help combine it.
Actually, we do not know what his DNA is exactlky like, but also, if you truely want to get into how they can be compatible, you have to look at the universe as a whole and how creatures came to evolve like they did.
Essentially, aslong as Kryptonians evolved in the same universe as Earthlings, and they are carbon based life forms who evolved into a humanoid form, it is most likely that their planet and it's life started off very much like ours.
Basically, the only true difference is that they simply evolved on a different planet, but would have still probably gone through, and cae from, the same things as our species and planet.
They simply have been around longer and thus evolved further, and also did so on a planet that did have differences that their bodies would also have developed to be adapted to.
Similar to how humans evolved on different continents, thus having never actually been together, yet they were compatible long before humans actually travelled cross water.
It is like taking the same basic organisms that we all evolved from and placing them on an other planet that can sustain life, and if they evolved to include humanoid species they would likely be compatible with us.
That is assuming our species in several thousand years would still be compatible with use now.
Also, a lot of differences can exist as well and they can still be compatible similar to how different species are too.