Gross

I was driving Joshua and Naomi up to school, this is part of their conversation:
N: ...that's gross.
J: What?
N: Mummy and daddy kissing is gross!
J: Ugh! Yes.
N: This is gross. (Not sure what this is as I couldn't see)
J: oooooh.  Dead bugs are gross.
N: ooooooooh.
As you can imagine I was cracking up!