Could Humans Marry Aliens?

A new Star Trek movie is out, granting everyone the chance to race around the galaxy with Captain Kirk and Spock. 

The first movie of the new continuity explored the marriage between Spock's parents.  Today I want to boldly go into a discussion of the nature of that union from the standpoint of Christian philosophy. 

Is it possible for humans and aliens to form a true marriage?

What is Marriage?

First let's define our terms.  The meaning of the word "marriage" is the subject of controversy today.  So we need to spell out exactly what is meant in this context.

The Western secular world adheres to what might be called "civil-marriage".  This is a conception of marriage as a purely legal arrangement between adults for the sharing of property and custody.  And if that is all "marriage" is, there is no reason why a human could not marry an alien.

However, we're looking at this from a Christian perspective. 

Christians subscribe to what could rightly be called "natural-marriage".  The nature of this marriage is discovered by applying reason to the design of our bodies.  For a full explanation of how that works, you can check out my [post] devoted to the subject.  But the result is something which meets these descriptions.

(These are meant to all motion to different aspects of the same thing)

• The complete union of spouses which enables the fulfillment of the complimentary design of their bodies.

• A lifelong union between man and woman oriented toward the good of the spouses and the procreation and education of children.

•  A union ordered to the creation of new families and the propagation of future generations.

So the question of whether a human could marry and alien boils down to this question:

Could a human form one of those with an extra-terrestrial?

Yes and No:

I'll divide this into three categories.

No:  Hannar, Mon Calmari

The first group are those for whom marriage would be utterly impossible.  These alien species reproduce in a way which is incompatible with human anatomy.  Or their genetics are so different from ours that the union could not form a new organism.  

Examples would be the jellyfish creatures from Mass Effect, the Hannar.  Also the Mon Calmari from Star Wars.  In each case it is impossible to create a human cross-breed with these creatures through natural means.

Thus, no marriage is possible.

Maybe?: Amphibiosans, Asari

Then there is a weird middle group.  Several sci-fi species do have the ability to create offspring with human beings... just not in the normal way.

The character Kiff from Futurama reproduced by absorbing DNA from another species through his skin.  The Asari from Mass Effect can do something similar.  In this case the union can create a child... but only through expression of one partners' biology. 

So here the answer would still appear to be no.  At least in my estimation, no marriage is possible here because there is no true bodily complementarity between the spouses.

Yes... if: Vulcans, Elves

Lastly we get to the case of Spock's parents.  Vulcan are essentially humans with funny eyebrows and pointy ears.  They can express full complementarity with the human body.  And this, as we see with Spock, produces offspring. 

However, there is one more caveat. 

In nature there are cases where different species can inter-breed, but the offspring is sterile. (This would be the case with mules.)  They are a generational dead-end, so to speak.

If the offspring between human and alien partners was of this sort, a true marriage would once again be impossible because the union could never be ordered toward the continuation of either race.  In other words, if every human chose to exclusively bond with one of these aliens, our species would go extinct after the first generation.

However, if the offspring is capable of contributing to further generations, then we are talking about true marriage material.

Live long and prosper.