We have a Kids Constitution that covers this subject. Here is what it says:
Rule 4-4-2
No wrestler will be permitted to wrestle another person with a weight spread exceeding the following weights:
8 & Under
15 Pounds
9 & 10
20 Pounds
11 & 12
25 Pounds
13 & 14
30 Pounds
15 & 16
35 Pounds