Contrary to popular belief, you should hold kittens as early as possible. The right time depends on how soon the kittens' mom will allow you to touch them without getting stressed. Early touch is necessary, because the window for taming kittens closes after the early weeks.
Newborns
The American Society for the Prevention of Cruelty to Animals says you can pick up a kitten from birth if the mother doesn't mind your presence, but it suggests you consult a veterinarian before you do so to kittens under a week old. The ASPCA also noted you don't want to wait longer than two weeks before starting to handle the kittens.
Pick a kitten up, hold him for a minute or two, gently stroking him, and then return him to his mom. It's important not to keep young kittens away from their mom for more than a few minutes at a time. Mom provides them nutrition, warmth and security, and must even stimulate them to potty. Only adults should handle young kittens. Young kittens are fragile and tiny, and even the best-behaved child may accidentally cause injury.
Mom
If the kitten's mom is tame, it is likely she won't mind you holding the kittens for a few minutes at a time. However, even some tame cats don't like humans handling their very young babies. If handling the kittens seems to cause mom stress, you should wait to begin socializing the kittens until they are a couple weeks old. If mom sees you as a threat, she's likely to try to move the kittens and hide them from you.
Toddlers
By the time they're about 2 weeks to 4 weeks old, kittens have opened their eyes and ears, and aren't quite so dependent on mom. This is the time when handling by humans is critical. Introduce kittens to other people so they don't become socialized only to you. You should try to introduce them to men and women alike. With supervision, you can introduce them to older children. During this stage, you may introduce them to a gentle cat-friendly dog, car rides and other common experiences. It's important at this age that kittens not be separated from their mom or siblings for too long at a time.
Play
By 7 to 8 weeks of age, most kittens can think of nothing but playing. It's important to teach your kittens that human fingers aren't toys. It may be cute when your kitten grabs your fingers, but it won't be so much fun when your kitten is a 12-pound cat with very sharp claws and sharp teeth. If your kitten grabs your fingers in play, redirect his attention to a toy. You may have to do this repeatedly during this stage, but it will be worth it when your kitten's an adult cat that doesn't attack your hands. Never encourage your kitten to play with your fingers and hands.
References
Writer Bio
Bethney Foster is social justice coordinator for Mercy Junction ministry, where she edits the monthly publication "Holy Heretic." She is also an adoption coordinator with a pet rescue agency. Foster spent nearly two decades as a newspaper reporter/editor. She graduated from Campbellsville University, receiving a Bachelor of Arts in English, journalism and political science.