Cassandra Clare said this quote

The posters bore the words WITH THE PASSING YEARS COMES...IMPOTENCE! Magnus found himself staring at the posters with a sort of absent horror. He looked at Alec and found that Alec could not tear his eyes away either. He wondered if Alec was aware that Magnus was three hundred years old and whether Alec was considering exactly how impotent one might become after that much time.