Here's the lesson we can all learn from this: Parents, let your kids get some sun. Rickets effects blacks because of the pigmentation in their skin, which blocks the sun's rays. Growing bodies need proper nutrition and the only effective way to get vitamin D is from the sun. Let your kids get some morning or late afternoon sun without sunblock everyday. You can supplement, but it's much better to get it naturally. If you do supplement, use the D3.
Just about everyone should supplement.
Unless you live south of San Diego or thereabouts, there is a good 3-6 months a year when the sun is simply not high enough in the sky for the UVB to get through.
No UVB, no Vit D.
Your heart is in the right place, but you've got the wrong supplement. Recent studies have shown that it's a phosphorous problem, not vitamin D or sunshine, a discussion on this page refers to the Harvard Medical study:
A paper published in March 2007 by Demay, Sabbagh and Carpenter Calcium and vitamin d: what is known about the effects on growing bone, should finally put the vitamin-D deficiency rickets myth to bed. The Demay group found that the metabolic cause of rickets is hypophosphatemia.This cause has been discussed since this 1857 paper, which suggests it was adulteration of flour with alum, that made the phosphorous in the flour indigestible that cause the rickets problem in London. Blaming the problem on VitD let the bakers off the hook.