Games : Crusader Kings 2 trait modding "birth" and "inherit_chance" attributes

If you create a trait with birth = 0 and inherit_chance = 100, does that effectively create a trait that only your ancestors can have?

In other words does the inherit_chance attribute take precedence over the birth attribute?

birth- Given number out of every 10000 characters born will receive this trait, (e.g., 100 = 1%)    

inherit_chance- A newborn can inherit the trait from a parent (optional); if both parents have the trait, uses two trials of same chance