Has this behavior been going on for the past 2 years? It sounds like the behavior may have something to do with your daughter being born. From his perspective, you got a new companion to replace him when you had your daughter, AND you had him neutered at the same time (adding to the displacement anxiety). Cats sometimes act out when a baby is born because there is inevitably less attention paid to them. This is just a guess, but I think your cat might be triggered by your daughter because for the past two years, every time your daughter has cried you have probably dropped everything to go attend to her. Your cat sees this, and associates your daughter crying with him not getting any attention. Then he goes to "mate" with the girls to try and get your attention, or in a misguided attempt to play with the girls. Your cat is jealous of your daughter. You should try to curb this behavior soon, or your cat may end up resenting your daughter and then scratching/biting issues could come into play towards her.