You might think we are a mad house, but a lot of us volunteer for rescues, and see first hand the effects of people allowing their cats to have just one litter (our first mum and kittens of the year have a very sad story), and also have to try and find homes for all the unwanted cats (I have 4 over the age of 8 here looking for homes, they were all wanted pets at one point), so can't always be pleased by letting cats have just one litter as there are lots of reasons against it.