Can you commit incest?

I want to know if you can have the offspring mate with one of his or her own parents. It's odd, yes, but I'm curious if Bethesda thought this through.

Edit: I'm going to cross breed, by this I mean like this

Parent 1 + Parent 2   Parent 3 + Parent 4
    = Child 1            = Child 2

Parent 1 + Child 2    Parent 2 + Child 3
    = Child 3            = Child 4

I hope this visual (somewhat) representation will show what I'm planning to do.

I believe there is actually a catch regarding parents/children. Instead of flirting, when you put them in the same residence the characters remark about "how nice it is to spend time with family". I am not sure how it affects subsequent generations though!

Putting two dwellers who were both born of the same two dwellers (ie siblings) in the living quarters will also give the "nice to spend time with family" message. So while you can almost definitely mate half-brothers/sisters, direct siblings are still counted as "family" and they won't reproduce.

You can't mate full- or half-siblings - if a pair of dwellers shares even one parent, they will not mate. You can't mate parents to their children. You CAN mate grandparents to grandchildren, aunts/uncles to nieces/nephews, cousins to cousins, etc. In other words, the game won't let you mate first-degree relatives, but everything else is fair game. Source: experimentation.