I think Creation and evolution should both be taught. In an argument, would you want to hear only one side of the story or both sides? It's the same with evolution and Creation. Only teaching the theory of evolution to children doesn't let them decide for themselves which one makes more sense.
You commit a logical fallacy here. Your argument is premised on the idea that there are only two competing theories; however, there are more. For example, the Norse used to believe that he world started as a hellish battle between the Southern Fire, Muspelheim, and the Northern Ice, Niflheim- from this chaos emerged Ymir, the first being. Ymir, a giant, created the first people while he slept, when they grew from his left armpit. Thus by denying alternatives, such as this simplified version of Norse mythology, you commit the fallacy of false dilemma.
Teach the controversy, you say, but what controversy? There are a myriad of conflicting stories about life's origins. To teach one "theory" based on religion but not the other, is to blatantly deny all other religions, but to teach all theories would expend our resources to no end. Thus it must be presumed that we ought teach no religious theories.
Still, people contend that their specific religious "theory" has evidence. But what sum of evidence is necessary to teach a particular religious theory? The Norse tale tells of Northern Ice and Southern Fire, clearly, their tale must be true because Greenland is in the north and the Sahara Desert is in the south. Likewise, all other creation stories have some partially factual premise, otherwise none would believe them in the first place. However, the difference between evolution and other theories lies in the comparable levels of known factuality. All pieces of evolution are supported by verifiable facts and the parts that are disputed are continuously having cross-verification done by leading biologists. The fluid nature of science allows evolution to have almost complete support by known facts, whereas other other religious theories have far less of an empirical base. I cannot prove for certain that Ymir was the first being as I cannot prove Adam was, those are unprovable assumptions. We must instead rely on the currently most complete and empirically supported theory.
Yet more, some argue that evolution has holes, thus justifying the teaching of other theories. This argument is fallacious, it suggests that something must have complete perfection to be taught. It is guilty of the nirvana fallacy. Moreover, we teach our students about gravity, yet our knowledge of it is still incomplete, why is gravity so much weaker than the other four forces of nature? To suggest we only teach things that reach the pinnacle of perfection excludes our ability to teach anything.
Evolution is the only theory to have justifications that should be considered universally reasonable as they rely on natural observations rather than abstractions into one's personal theory of creation. To teach anything other than evolution discriminates against religious theories that are not taught. Therefore, within the bounds of the public education system it is the only theory that ought be taught.
