Cat Experts! Introducing New Kitten?

my cat is 12 years old a tomcat and a real home cat, he's very afectionate and loves are attention, we did used to have 2 others but they died about 5 years ago... were thinking of getting a kitten but would this affect my cat? i wouldnt forgive myself if he ran away....would a female or male be better and what would be a way of introducing the kitten to my cat?