[Defiance] An alien cuckoo?

Something bothered me about Alak Tarr from the moment I saw him...

He doesn't look anything like his mother or father. And it is not just the hair (which is likely dyed).

It is his eyes...

Click to embiggen...

Note the description of the Castithans from the Defiance site:

Although they are conservative with regard to tradition and language, Castithans tend to be very liberal with their sexuality. Sex is as much a tool of political agenda as it is an expression of love. Castithans have zero reservations about using sex as a means to an end. That’s not to say that Castithans don’t also enjoy sex to the extreme. Many of their most cherished ceremonies involve expressions of passion and desire.

I get the feeling that along with this goes the cultural reality that, as far as society is concerned, "the children of a man's wife are his children, regardless of their actual genetic parent." How else could it work in a society so worried about caste and social class?

The show very purposefully put together a group of actors who very much looked alike, and "pure" to the Castithan type, especially so in the case of Datak and Stahma... 

So... who is Alak's father? And is he even a Castithan? Could his father be human?

Though Datak very much emphasizes "my son" several times, even when with Stahma... could it be that Stahma is not his mother? Hmmm...