Board Thread:WARNING ALL USERS False Info\Spoilers/@comment-97.81.194.170-20131123020248/@comment-4091815-20131123025131

Anything that can heal, will heal.

A crushed brain, Ennis' for instance, could not heal because the brain doesn't repair itself like that.

Broken bones mend. Damage to the testicles can heal - but the scenario you present - the crushing of the testicles - may be similar to removing them altogether. If that were to happen, they would not "grow back".

The closest equivalent we have is Deucalion's damaged eyes - they could not heal to full function and remained scarred long after the damage was done.