Thank you for your reply. Yes, to have him neutered may be the best way for me to stop him from spraying but as you mentioned chances are he may not quit his spraying habit that I don't know. He has just started spraying inside a house for less than a year although he is now 7 years old. He was a feral cat who came to my house 3 years ago and I adopted him since then. He stays pretty much in a secured garden when I am not home. He only stays in when I am in and goes to bed with me almost every night. He was once away for 12 days which I thought I probably lost him but he only went out for girls! Well, to have him neutered might helps that too. The reason why I am reluctant to do so is I still want him to enjoy his full male cat's life and also I heard that once neutered male cats tend to lose ability to protect themselves from other male cats when they attack. Besides, will a cat get fat or bloated and be less active? My cat is pretty round about 10 lbs.