1. If EVERY cat/dog was fixed, there would very shortly be NO more cats and dogs. I realize that's not a problem we currently have, but I get tired of people freaking out at the idea of a single non-fixed animal, without realizing that they cannot possibly all be fixed if the species is to continue. 2. Maybe they actually breed cats, to sell. If they breed purebreds, especially of certain rarer or more difficult breeds, they can sell for hundreds of even thousands of dollars per cat. 3. Maybe they adopted the cat when it was already pregnant, so there wasn't much they could do (other than cat-abortion) and they were planning on getting it fixed as soon as the kittens were born. 4. It's also possible that they underestimated the age at which cats are capable of becoming pregnant (VERY young), and hadn't gotten around to it yet because they didn't realize it was necessary (in which case it's the vet's fault for not saying anything).

THANK YOU. My mom and I foster pregnant cats (something a lot of people won't do; OP pointed out why), but every time I mention my cat giving birth, I get a lecture on the benefits of spaying and neutering. What people like 240 don't understand is that no matter how much people try to fix their pets and make sure cats get fixed, stuff like this happens. First-time cat owners don't know how young a cat can be when she goes into heat. I doubt this person was a cat breeder, because they would know why you don't let your cat into your bedroom when she's due, but it could be a situation like mine, where they adopted a pregnant cat. Glad to know there are people on my side. OP, next time you have a pregnant cat, keep her in a separate room (usually a bathroom) when she's due. If you don't know, just lock her up every night and when you're out of the house until the babies are born. Also, give her a box with an old towel or some newspaper inside so she can have a proper nest. Good luck with the kittens!