A response to Homologuephobia, by Gregory A Petsko, Genome Biology 2001 2:comment1002.1-1002.2, to An apology for orthologs - or brave new memes by Eugene V Koonin, Genome Biology 2001, 2:comment1005.1-1005.2, and to Can sequence determine function? by John A Gerlt and Patricia C Babbitt, Genome Biology 2000, 1:reviews0005.1-0005.10.