Cue an Impossible Task, search for a non standard heir from outside the family (who has a statistically abnormal chance to be an orphan/bastard child of the retiree), or otherwise trying to reform their potential heir or forcibly change them one way or another.
In order to keep everyone in line, the leader of the facility gives anyone who doesn't want to take the standard drugs a different medication that makes them kill after transforming, which convinces everyone else that their abnormal side is to be feared and kept hidden.