Well, in answer to your first question, yes they can; however, cats generally only want to mate if they are not fixed and it is mating season. Does that stand for all cats, no. Like us, cats are all different and they all respond differently to stimulus. For your second question, male cats are particularly troublesome if they are not fixed. I generally suggest that all cats be fixed to help prevent many common cancers. This procedure will usually reduce your cat's desire to go outside, spray on furniture and/or behave erratically.