Can Aliens with DNA Reproduce with Humans?

Humans cannot mate with some spies on Earth. Why would you think an extraterrestrial entity could? Perhaps they could be seeded. That is what Earth's scientists would try to do. But even if extraterrestrial life forms have DNA, the possibility of human and alien reproduction still seems highly unlikely.

Understanding DNA Reproduction

Just having DNA doesn’t mean two creatures of different species can interbreed. The number of chromosomes, the physics involved, and many other factors must match. The interoperability of two different species in reproduction is not feasible without significant genetic and biological alignment.

Do Aliens with DNA Exist?

Every organism on Earth, from animals and plants to fish and insects, has DNA. So how many of them are able to reproduce with humans? This alone suggests the immense biological barriers to inter-species reproduction.

Imagining Alien DNA

Let's imagine the following scenario. The aliens or extraterrestrials are carbon-based like us and share the same amino acids with our RNA uses: Adenine (A), Cytosine (C), Guanine (G), and Thymine (T). Each codon, a three-amino-acid combination, allows for 64 possible combinations. A typical strand of RNA/DNA contains thousands to millions of codons, suggesting an astronomical number of possibilities.

Genetically, if they share the same scheme of life as humans, they would share the same genetic rules. But unlike humans, elephants, octopuses, birds, trees, slugs, spiders, tapeworms, fish, dinosaurs, monkeys, wood ticks, and countless others, they would still be a different species. Their planet might be identical to Earth in terms of atmosphere, hydrosphere, lithosphere, gravity, and stellar environment. They might even have a similar geophysical history, but that would not make them identical.

Biological Barriers to Reproduction

The fact that extraterrestrials would still be genetically different from humans, much like penguins, makes reproduction between the two separate species extremely unlikely. Even if extraterrestrials were super intelligent and thousands of years advanced in technology, human genetic differences would likely prevent successful reproduction. No matter how advanced they are, the fundamental biological differences would still present a significant challenge.

Conclusion

Unless extraterrestrials have discovered ways around the natural barriers to reproduction, inter-species reproduction between humans and aliens is highly improbable. The biological differences are simply too great, and these complexities cannot be easily overcome.

So, while the concept of cross-species reproduction may seem fascinating in science fiction, the reality of genetic and biological differences makes it a highly unlikely occurrence in the real world.