I have a nearly 4 year old neutered female cat. I have been thinking about adopting another cat, but I fear they won't get along. Current cat is not really social, rarely likes being touched, instead requires attention: playtime, being near (but far enough), etc.
What are your experiences with second cats? Are there age / gender combinations which are the safest?
Edit: thanks for all the replies! Forgot to mention that she is an indoor cat.
Not siblings, but they are related through the same breeder. Casper is 4 years old, Mocha is only 9 months. I've had Cornish Rex since about 2001, with new additions as previous ones passed away. We never really had any problems after the first 2-3 week introduction period.