Let me first say that I'm a big fan of Superman, as even a cursory look around this blog would demonstrate. As a science teacher, I'm also a big fan of science. In most regards, Superman's status as a science-age superhero with ties to pulp science fiction means that I get to enjoy both at the same time. And even Superman's more outlandish abilities at least offer the opportunity for interesting speculation on how they might function.
Recently, I've had particular cause for celebration, since the excellent Chris Roberson brought remarkably accurate and cool physics concepts into his "Superman/Batman" plot. Sadly, I've also had cause for consternation, since J. Michael Straczynski's "Earth One" graphic novel mangled several basic science topics. But a glance at various credits pages suggests that you deserve major kudos for the former and weren't involved in the latter. So your record on Superman's super-science was quite positive, in my estimation.
Until the most recent Ask Matt column at the Superman Homepage. When asked whether or not Superman's X-Ray vision was radioactive, you said:
It is indeed radioactive, Calvin, but it depends on how concentrated an x-ray Supes is firing at a given moment. He obviously would prefer not to go around irradiating everything he looks at, and makes a concerted effort not to.And that makes me scratch my head. See, I have to wonder why Superman's eyes would fire X-Rays? Sight works not because light comes out of the eyes, but because light comes into the eyes. Were Superman to fire X-Rays from his eyes, he'd only see what was reflected back, which, with X-Rays, wouldn't be much. There's a reason that doctors and dentists put the X-Ray film on the opposite side of the bone from the radiation source, and not the same side. Projecting X-Rays certainly wouldn't account for the full-color, detailed images that we typically see Superman receiving.
The conventional wisdom, as stated in (for instance) Mark Wolverton's The Science of Superman, is that Superman’s X-Ray vision is actually a matter of receiving and interpreting a large range of visual input from across the light spectrum, specifically focusing on the wavelengths and frequencies that would pass through solid objects. The ability as typically portrayed is still at least a little farfetched, but at least it doesn't necessarily involve Superman single-handedly increasing the cancer risk all across Metropolis.
I write this not in hopes of being one of those nasty nitpicky folks, but in the interest of promoting good science in comics that, at least recently, have had a pretty good track record in that regard. I hope you accept this in that spirit.