I wrote a paper in 9th grade (13 years ago) about the effects of rising dioxin levels on human fertility statistics. If it's indeed true that human male fertility has been falling steadily since the 1930s, dioxins are most likely the reason. Because they are estrogenic and can cross the placenta, they can cause numerous other birth defects as well, including undescended testes, hypogonadism, micropenis, hermaphroditism, other intersex conditions, and gender identity disorders (if a male fetus' brain or body - but not both - develops in a typically female way because of the presence of dioxin). In mice, it produced male mice who would assume the typically female position with other males, and who were infertile.
The continued presence of dioxins in the environment may well lead to the extinction of the human race, not now or even in 50 years, but whenever the concentration in our tissue (which increases with successive generations) is high enough that none of us are fertile anymore. Of course, by then we'll probably be able to create new people via in-vitro or cloning.
If a tattoo (or piercing or other body-mod) is an expression of your religion - particularly one that your religion or cultural group required of you - then it is likely protected under the First Amendment and employment non-discrimination laws. While this is pretty rare, I know it's traditional for Maori to get tattoos (even facial tattoos) as part of a cultural tradition, and I know of at least one Native American ceremony (the Sun Dance) that involves piercing. I'm sure there are other. If you're wiccan, and the head of your circle or coven tells you it's important for your spiritual development to get a particular tattoo, that might even be enough... as might a Celtic-looking tattoo if you're Irish and trying to display your cultural pride. Asking you not to display such devotional tattoos / piercings at work would be akin to asking an Orthodox Jew not to wear fringes, or asking a Sikh to take off his turban - in other words, very illegal. Especially if your company doesn't have a well-stated anti-tattoo policy.
If your tattoo was just for shits and giggles, though, it's your own fault for not getting it in an area that's easily covered with clothing. And if companies can now refuse to hire tobacco smokers - or medicinal marijuana smokers in states in which such things are legal - then I'm sure recreational tattoos are no different.
I bet this is a case of the superintendent or someone on the school board being a rabid Mac-head, and like all rabid Mac-heads, trying to convince as many people as possible to join the "one true way" by whatever means necessary.
And let me be clear, I have a Mac and an iPhone. I like them both quite a bit. But seriously, some of you Mac cultists creep me the hell out.
MESSAGE ACKNOWLEDGED -- The Pershing II missiles have been launched.