Trigger Handler
================

trigger CreateChildTrigger on Account  (after insert, after update) {
	CreateChildHandler.createRecord(Trigger.old, Trigger.new);
}

Controller
===========

public class CreateChildHandler {
	
	public static void createRecord(List<Account > lstOld, List<Account > lstNew) {
		List<Hobbies__c> lstNewCL = new List<Hobbies__c>();
		
		for(Integer index = 0; index < lstNew.size(); index++) {
			Hobbies__c objCL = new Hobbies__c();
			String oldPicklistValues = '';
			String newPicklistValues = '';
			
			if(Trigger.isUpdate && (
			  (lstOld[index].Country__c != lstNew[index].Country__c) 
			||(lstOld[index].State__c != lstNew[index].State__c)
			|| ...
			|| ...)) { //Add all 15 fields here with OR cndition like added for "Country" and "State"
				objCL.Account  = lstNew[index].Id;
				
				if(lstOld[index].Country__c != lstNew[index].Country__c) {
					oldPicklistValues = oldPicklistValues + lstOld[index].Country__c + ',';
					newPicklistValues = newPicklistValues + lstNew[index].Country__c + ',';
				}
				if(lstOld[index].State__c != lstNew[index].State__c) {
					oldPicklistValues = oldPicklistValues + lstOld[index].State__c + ',';
					newPicklistValues = newPicklistValues + lstNew[index].State__c + ',';
				}
				.....
				..... //Add if condition for all remaining pikclist here
				.....
				
				//Finished if, then
				objCL.Old_value = oldPicklistValues;
				objCL.New_value = newPicklistValues;
				objCL.action = '';
				//Add Other required fields 
				
				lstNewCL.add(objCL);
				
			}
			else if(Trigger.isInsert) {
				objCL.Account  = lstNew[index].Id;
				newPicklistValues = lstNew[index].Country__c + ',' + lstNew[index].State__c + ',' + <............. Add all remaining fields here>;
				objCL.Old_value = ''; //There is no old value.
				objCL.New_value = newPicklistValues;
				objCL.action = '';
				//Add Other required fields 
				
				lstNewCL.add(objCL);
			}
		}
		
		//Insert record
		if(!lstNewCL.isEmpty()) {
			insert lstNewCL;
		}
	}
	
}