REPRODUCTION

Gestational period of the cat:

The cat gestation period is generally defined in most textbooks as: the number of days between a "successful mating" and the birth or parturition of the fully developed kittens. Depending on which textbook you read, the cat gestation period is generally stated as being somewhere between 61 and 69 days long, with an average of 63 to 66 days. The reason for the huge variation in the figures stated for the length of the cat gestation period is the nature of the feline reproductive cycle itself.
http://www.pet-informed-veterinary-advice-online.com/cat-gestation-period.html

How many offspring does cat typically have at a time?

Unlike people, our furry companions are capable of giving birth to kittens throughout their senior years, according to the Coronado Cats in Phoenix Arizona. While their reproductive ability might decrease, they don't go through menopause like a human female does. This means kitties can give birth to kittens during their entire life. Theoretically, your feline companion can give birth to three litters of kittens per year, with an average of four kittens per litter, in an average lifetime of 15 years for an indoor kitty. This could result in up to 180 kittens in her lifetime. Assuming that her litters remain intact, and breed themselves, hundreds of thousands of kittens could result, contributing to the pet overpopulation problem. Even though all of these kittens won't likely survive, even a fraction of this number is way too many.
http://pets.thenest.com/average-many-kittens-can-one-cat-one-year-7043.html

How long do the offspring live with the parent?

A kitten should stay with its mother for an absolute minimum of eight weeks and preferably 12 weeks. Although they may be "weaned" prior to eight weeks, they will still have the occasional need to nurse. Kittens taken from their momcats before this time often develop nursing behavior on themselves, other cats, humans, or fabric, and these habits will often continue throughout adulthood. They also need this time to learn proper cat behavior from their mother cat, including use of the litter box, socializing with humans and other cats.
http://cats.about.com/od/kittencare/f/timemomcat.htm