Can your cat have one kitten?
Although it is supposed to be a rare case, it definitely
happens. I have a cat who just gave birth to one herself. I have
read that it can happen in young cats, first litter, and also
depending how many mates she has had. But as long as mommy and baby
are fine I wouldn't worry about it at all. No need to stress if
there are babies that escaped mommy's bed. She'll keep them