This question is in my JLPT practise book:
親{おや}のしつけが子供{こども}の性格{せいかく}形成{けいせい}に＿＿＿＿ことは言{い}うまでもない。
A 通{つう}じる B 通{とお}す C 関{かん}する D 関{かか}わる
The book says the answer is D, but to me the definitions of C and D overlap so much that I can't see why one is obviously better.
So what's the difference between 関{かん}する and 関{かか}わる?
Both Xに関する and Xに関わる have the overlapping meaning when it comes to 'concerning or related to X'.
However when you see XがYに関わる or Yに関わるX it is probably better than 関する when X is something that directly affects Y, or is something that Y is dependent upon. Also, there is the nuance that Y is a big or serious thing such as education, peace, life.
For example you might say 治安に関わる仕事 when talking about policemen to show the large degree in which peace (public order) is a result of the police.
You may also say 治安に関する仕事 but then it's means more something like a job that has something kind of connection to peace, and would not be as complimenting as the above example.
I'm going to make sure you understand the sentence structure here correctly.
This こと is a nominalizer and does not mean "things".
Focusing on the first part:
親のしつけが子供の性格形成に（関する・関わる）。（そんなことは言うまでもない。）
The former means "relates to"; the latter means "has a significant effect on". 関する is also rarely used to end a clause like this; it's more common as the structure Xに関するY.
かかわる@プログレッシブ和英中辞典@Yahoo!
それは命にかかわることだ
It is a matter of life and death.
