Are you honestly comparing crystal meth from the street to something prescribed under the guidance of one's doctor? Your post strikes me more along the lines of hysterics than a rational foray into discussion.
For shits and giggles, let's compare apples to apples. Desoxyn (Methamphetamine HCl). There you get the scary M word, but one that's FDA-approved and prescribed--though, admittedly, not commonly--by doctors. Same chemical substance minus the crystallized form, impurities, and of course, the world of illicit meth.
Oddly enough, Abbott Pharmaceuticals isn't synthesizing Desoxyn in their backyard meth lab ala shake-and-bake and Walgreen's isn't hawking it from the saddle bag of their pharmacists' motorcycles. Same substance, different context.
If you want to argue against possible long-term effects of d-amphetamine on developing children, do so. You certainly won't be alone, though for all the hysterics and despite thousands of long-term studies on its effects, there's a rather glaring dearth of support for that position. But, hey, "methamphetamine!"