The following article explains how to create sets of Yes No checkboxes that are mutually exclusive. That is when you check the Yes box the corresponding No box is unchecked.
The HTML below shows how this can be achieved :
<html>
<head><title></title></head>
<body>
<script language="JavaScript">
<!-- Begin
function CheckBoxesByName(sName,sMode)
{
}
// End -->
</script>
<p>
Yes<input type="checkbox" checked="yes" name="cbox_yes_1"
onchange="CheckBoxesByName('cbox_no_1',2)">
No<input type="checkbox" name="cbox_no_1"
onchange="CheckBoxesByName('cbox_yes_1',2)"></p>
<p>
Yes<input type="checkbox" checked="yes" name="cbox_yes_2"
onchange="CheckBoxesByName('cbox_no_2',2)">
No<input type="checkbox" name="cbox_no_2"
onchange="CheckBoxesByName('cbox_yes_2',2)"></p>
<p>
Yes<input type="checkbox" checked="yes" name="cbox_yes_3"
onchange="CheckBoxesByName('cbox_no_3',2)">
No<input type="checkbox" name="cbox_no_3"
onchange="CheckBoxesByName('cbox_yes_3',2)"></p>
</body>
</html>