Why is she a half-alien?
Either I've missed it, or it was not explained: why is Lexi in Falling Skies a half-alien?
The only explanations I have are "just because", "due to the eye bug", and "because of something unmentioned that happened to Tom on the alien ship", but all of these seem weak and Googling didn't really help.
Addendum: Falling Skies wikia lists The Monk and Karen under her "family" as her DNA donors. However, the texts don't explain this and I still cannot place it in the timeline. Those two had access to Lexi after Karen captured her, but that only happened because Anne has already discovered Lexi's mixed DNA which made her escape the camp. Any thoughts are welcome.
Best Answer
As far as can be seen, it has not been adequately explained either in or out of universe. One predominant fan-theory (e.g here) is that when
Tom was held captive by the Espheni between seasons 1 and 2
his DNA was somehow altered which was passed onto Lexi. There are no official sources confirming this that I can find though.
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