Instructions
Start by paying attention to the mother cat. Pet her gently, speaking softly to her in order to put her at ease. You might also want to have cat treats or some other food that you can give to her, as this will not only help to keep her calm but will also give her needed nutrition while she is nursing.
When the mother cat seems calm, move your hand slowly toward the kittens. Keep an eye on the mother to see if she's watching your hand, paying attention to see if she hisses or otherwise seems upset. If she does get upset, slowly move your hand back to her and start petting her again to show that you aren't a threat.
When you do start petting the kittens, do so very gently with the tip of your index finger. The kitten might hiss at you or make tiny meowing noises; as always, keep an eye on the mother cat in case she decides that you're trying to hurt one of her kittens when the kitten starts making noise.
If you wish (and if the mother cat doesn't seem upset at the time) you can very gently pick up the kitten to hold it while you pet it. Do this by putting your whole hand beneath its body and scooping it up. Pet it gently as before. Keep in mind that it's almost assured that the kitten will start meowing, and that the mother cat will be watching intently. If the mother cat starts growling or hissing, put the kitten back with the others.
Kittens tire easily and need to eat often, so don't keep a kitten away from its mother for too long.
How to Pet Newborn Kittens
To a cat lover, the urge to pet a newborn kitten is almost irresistible. It's important that you don't let this urge override your sense of caution, however, because not only can you hurt the kitten if you're too rough but you also might make the mother cat angry if she thinks that you're scaring or hurting her babies. Here's how you can pet the kittens without causing any problems.