Question about some children's bonuses

[Tuidjy]

When a child gives, for example, a 20% bonus to defense, what is the bonus
applied to? I can think of the following possibilities:

+20% of the creature's original defense
+20% of the hero's total defense bonus
+20% of the hero's native defense bonus, i.e. before items and other kids

Does anyone know for sure? If one has ever gotten a +20% defense/attack
kid, it should be simple to check.