Our 3month old male kitten...

Question
Our 3month old male kitten who was (is?) litter trained is now (last 2/3 days) urinating on furniture and in sink, WHY? HELP????
Thank you. CJ

Answer
Hi CJ!
I would definitely have your veterinarian check your cat and his urine to see whether or not this is caused by a urinary tract infection.
Cats generally reach sexual maturity by the ages of 6-9 months.  It would be uncommon but not impossible for him to be developing the full grown, intact male instincts early, causing him to mark his territory. In which case, neutering may help.
Until you can get to your veterinarian's office, place your cat and a clean litterbox in one room (maybe the bathroom to avoid any messes on carpets).  Show him the litterbox again and keep him there overnight.  With the litterbox in close quarters, this may encourage him to use it.  The next day, let him roam his usual space and place him in the litterbox several times during the day to encourage him to use it.  Keep the litterbox very clean, as some cats can be picky about going in a litterbox that has been used several times.
Also, if you have changed his normal litter to a different brand, this can also cause confusion, so it may be helpful, if you have changed it, to change it back to the original litter.
If you are still noticing that he is not using it, it would be best to have a vet check to make sure all is well.
Urinary tract infections can be cured by a dosage of antibiotics for the course of approximately 7 days.
I hope this helps!
Hilary