Water cycle
From Tardis Wiki, the free Doctor Who reference
According to Jack Harkness, by the 2000s, oestrogen entered the water cycle when people flushed their contraceptive pills down the toilet: sending the hormone "all the way up into the sky, [then] all the way back down on to me" via rain. Jack further claimed that this was "feminising" the fish. Nevertheless, he was happy enough to avoid another pregnancy. (TV: Everything Changes)
