Q: This nitwit I work with got two cute kittens at the end of last summer from the same litter, male and female. (At least she went to the shelter!) She didn't take either cat to the vet, and now the female seems to be pregnant.

Because the cats go outside at will, the father could be any cat, I guess. But we got into a disagreement because she said it could be any cat except the pregnant kitty's brother. (She says she read that brother and sister cats won't breed.) I think it probably was the brother, since he's at hand. What do you think? -- W.P., via e-mail

A: It could be the brother, it could be a neighborhood tom, or it could be the brother and any number of neighborhood toms. That's because it's perfectly possible that the kittens have multiple dads.

Your e-mail reminds me of a phone call I received a few years back from a woman who couldn't understand how her dog kept getting pregnant. She swore to me that the dog was never left outside unattended and was never walked without a leash. No dog could have gotten to her anyway, she said, since the dog's own son was always with her, and he didn't like other dogs.

I asked her if the male had been neutered and, as I guessed, the answer was "no.Ó I told her it was highly likely that the father of the puppies was also their brother. She seemed shocked and didn't want to believe me.

"Don't they know they're mother and son?Ó she asked.

The dogs neither know nor do they care, I told her. If the dogs aren't altered, they'll do what dogs do in such situations. Mother-son, father-daughter, siblings, no matter. And yes, cats will happily do the same under the right circumstances.

In other words, blood relations don't count for much. So tell your co-worker not to count on an imaginary feline prohibition against incest to keep littermates from mating. I tried to encourage the woman with the two dogs to get them altered, and I hope you will encourage your friend with her two cats to do the same.

At the very least, getting her pets altered will make them better pets in addition to not adding to the number of kittens trying to find homes every year. (Also, her cats will be perfectly happy and less at risk of illness or injury if she keeps them safely inside.)

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