How To Introduce A Kitten To Another Cat?

I want to introduce my kitten, who is 6 months old, to another cat. I live in an apartment with no yard and the cats can’t be separated at night (they sleep together). What should I do? They’re not toys; they’re real cats! Can you suggest a good way to help them get along? The second question was asked by Lucy M., age 12: My sister’s cat died several weeks ago. She has two kittens now. We are planning on giving one of the kittens away for Christmas this year so that our other children will have a pet. Our family is very small because we are only allowed two pets per household member due to allergies, but still have four kids under 2 years old. So what would you recommend as being both fun and educational for us all while teaching responsibility?:

Traditionally, it used to be thought that if your new or young kitten were spayed or neutered before its first birthday then there was less chance of problems developing later down the line between him/her and your other cat(s), although studies have suggested there may not be any difference at all between intact males and females in terms of their fighting ability – which has led some vets over recent years to advise owners against neutering their cats until after their second birthday anyway…