Meh, I even question myself on this at times..well whether he is or isn't really isn't any of our business now is it? Personally, looking at ALL the facts though, I would say a strong possibility. I mean, he made Naruto and Sasuke kiss BEFORE fan service could even begin on those two...(unless he wanted it) It is also in a Shonen manga aimed towards young boys. He pretty much SUCKS at creating female characters (if you like girls alot or even the slightest, wouldn't you t LEAST have an idea of your ultimate female's characteristics?) His girls are very underdeveloped and aren't half as strong as the men, with a FEW exceptions like Konan and Tsunade etc. (Again, I know it's a shonen manga, but wouldn't boys want to see a strong female character? I dunno...) Also, making Madara sexist (though this may OR may not have absolutly anything to do with Kishi, just an assumption) says alot about him in ways. Stop living in the past Kishi, sexism may still exist, but don't make it look like it's "okay" (I mean, literally making the mothers in that episode fight with the pots and pans was just...wooow) Not a good thing to teach young boys personally. So, yeah, with lots of drawings of Naruto and Sasuke art that look "yaoi-ish" (must be to attract more girls I assume) So, even if Kishi is "gay" does it really matter? Not really. Doesn't effect our lives, and if he ever did come out, don't be surprised.
Also, I think Wikipedia says he is married anyways, but you know Wikipedia...anyone can edit it so lol