Rad Child (Fallout: New Vegas)

Rad Child is a Fallout Tactics Perk. So far it hasn't appeared in any other game.

You do not take immediate damage from radiation. In fact you gain extra healing while being exposed to it! However, radiation continues to build up in your system as normal.

Fallout: Brotherhood of Steel
Rad Child is also a Fallout: Brotherhood of Steel skill. It restores health when exposed to radiation. Available only to Cain.