Summarize the following:
A cat's scratching is a normal defensive behavior, and punishing a cat for scratching can lead to further aggression in the future. You can trim a cat's claws at home with regular nail clippers. Clipping a cat's claws once a week can minimize damage from future scratches. Try not to play roughly or aggressively with your cat or kitten. This may encourage them to bite and scratch you and other humans. Most cats outgrow excessive biting and scratching once they pass from a juvenile to an adult cat, between 1 and 2 years of age. If you are sensitive to cat scratches or are immuno-compromised, you should consider adopting an older cat as a pet instead of a kitten.

Summary:
Do not punish a cat for scratching you. Clip your cat's claws. Avoid rough play. Adopt an older cat.