Well ,I think there is no harm in giving kittens milk because cats love milk.I ,too often give my cats their kittens milk.

 I have raised dozens of kittens (on a farm) If you got the kitten at such a young age that it will only drink milk, I would put a little in a syringe and the baby will suck on the end like a nipple with you gently pressing the plunger. As soon as the kitty will eat hard/soft food, all he/she will need or want is water.