Then aren't you glad you posted to Usenet ?

an 8 wk male kitten isn't going to be doing any spraying, that behaviour
starts at "puberty"; 6 months or so, by which time you'll have him
neutered so it won't happen at all.

pat

I think 'unknown' is an idiot. A nice laid back male is usually an easy
addition to a home that already has a cat or two. A male kitten, as someone
else mentioned, won't be spraying... but male or female, kittens are more
active and playful, and might spark some anger out of the first cat if the
little one wants to play and the established cat doesn't.

Female cats can be added to a household just as easily. It -always- depends
on the cat. Honestly, with an adult cat in the home, you're better off
asking the staff or volunteers at your local shelter if they can think of
any adult cats that would fit your situation best.

um, a male and a female are usually of the same breed.. its gender that you
were looking for.
and cats neutered before puberty are "gender inspecific" as I like to say.
Im a house hold with six, four males two females.  I find the most fighting
between the cats that are of the same coloring.  No idea why that is, there
is no specific science behind that.. but my gray and white girl HATED the
gray and white kittens I was considering adopting, and my solid gray cat
hated (and this is bizarre since he loves everything) the little gray kitten
I was considering (yes, I foster, yes I consider it a lot, and yes, I know I
should stop that ;D)

I honestly don't think it matters what you get, as long as they are all
neutered, and you do the introductions in the proper way showing a great
deal of respect for your resident cat.  Google cat introductions and you'll
find lots of helpful information.