Absolute monsters.  I have no medical training whatsoever, but I'd have bet my life savings that such blockers were not safe.  There is no defense for interfering with a human child's natural growth processes.  How could anybody with reasonable intelligence think interrupting processes that occur once in a lifetime could be reversible?  It's not like hitting pause on your DVR.  Now somebody will chime in and say that puberty was successfully interrupted and restarted in rats, and I don't care.....