In the following code sample...

<apex:selectRadio value="{!CustomObject__c.CustomField__c}" >

  <apex:selectOption itemValue="true" itemLabel="Yes" />

  <apex:selectOption itemValue="false" itemLabel="No" />

</apex:selectRadio>

The second item "No" is selected by default. I want the first item "Yes" to be the one that is, by default, the selected item.

Steve