Kitten

Although domestic kittens are commonly sent to new homes at six to eight weeks of age, it has been suggested that being with its mother and litter mates from six to twelve weeks is important for a kitten's social and behavioural development. Usually, breeders will not sell a kitten that is younger than twelve weeks, and in many jurisdictions, it is illegal to give away kittens younger than eight weeks old.
Health
Domestic kittens in developed societies are usually vaccinated against common illnesses from two to three months of age. The usual combination vaccination protects against Feline viral rhinotracheitis (FVR), Feline calicivirus (C), and Feline panleukopenia (P). This FVRCP inoculation is usually given at eight, twelve and sixteen weeks, and an inoculation against rabies may also be given at sixteen weeks. Kittens are usually spayed or neutered at approximately seven months of age, but kittens as young as seven weeks may be neutered (if large enough), especially in animal shelters. Such early neutering does not appear to have any long-term health risks to cats, and may even be beneficial in male cats. Kittens are commonly wormed against roundworms from about four weeks.