Like the title says, but let me clear up the question a bit.
If a human (lilin) comes into contact with any of the 13 angels (adam), would an impact start? From my understanding, it would, as the angels are Adam's children, and humans are Lilith's children. If something like this can happen, then touching an Evangelion born from Adam would cause an impact, right?
Is this explained anywhere in the manga, anime or movies? I can't seem to remember anything relating to this topic.
No, nothing would happen.
This can be seen with Eva Unit 01’s (a Lilith-based lifeform) fusion with material from the Fourteenth Angel (Adam-based lifeform). Same thing with Kaworu (albeit in a Lilin body, touching Shinji). Same thing with the Adam embryo (albeit missing the soul) on Gendo's hand.
It was implied that simple contact doesn’t result in an impact. What happened in the Contact Experiment with Adam, aka the Second Impact, is unclear, along with who the donor of the DNA for Kaworu Lilin body is from (Rei's is Shinji's mother).
