Today is
Spay Day. I really don't understand people (other than breeders) who don't get their pet spayed or neutered.
I've known people who wouldn't do it because "it doesn't look right." My Dad claimed his dog wouldn't want it; "how would you like to have yours cut off?" Honestly, Dad-- if the only action I was getting for the rest of my life was your leg, I think I'd be begging to get them taken off (and reduce the chance of getting cancer to boot). Are you projecting a little?
If it's a question of money, maybe you can't afford a pet at all. Can you feed it reliably? Can you get it care if it gets sick? You can get it done at a reduced price with a little effort.
Besides the animal's health and happiness, lets face it: no matter how good a parent you are, there is a good chance your animal will slip out of the house at some point when it (or a nearby stray) is in heat. You are being selfish and irresponsible and potentially bringing more puppies/kittens into a world where animals are already being regularly euthanized due to overpopulation. You are also being selfish and irresponsible because your "beloved pet" may have health risks (besides being unhappy). Don't be a jerk; spay/neuter!