Old Jewish joke. A group of Ukrainian villagers are trying to get a cow to mate with a bull. Try as they might, the cow refused to mate with any bull at all. The villagers take the cow to the rabbi to ask for help. The Rabbi inspects the cow then asks the villagers, ""is the cow from Kiev?"" ""Yes..."" replied the villagers. ""Aha,"" exclaimed the Rabbi ""that's why she won't mate with the bull."" ""How do you know this?"" asked the villagers, intrigued. ""My wife's from Kiev."" replied the Rabbi.