Input loop always chooses last option

I'm pulling data from a table using PHP.  The data goes into a form with inputs.  The data in the form is good on the page, but when I click the 'submit' button, the only data that's posted is the last record.

I uploaded a test page here...

http://testregister.cenational.org/admin/commitment/test.php

that goes to a page that echos the POST.  It must be something simple I'm missing, so any ideas are appreciated.

Here's the code of test.php

<?php 
	$id_commitment='testCommit';
	$id_event='mo14420';

	//Store registrants into array_registrations
    try {
		$qry_registrants = new PDO("mysql:host=$xxxxx=$xxxxx",$xxxxx,$xxxxx);
	
		$sth = $qry_registrants->prepare("SELECT 
				table1.fm_lname,
				table1.fm_fname,
				table1.id_family_member,
				table2.f_city,
				table2.f_state
			FROM
				table1, table2, table3
			WHERE 
				table2.id_family=table1.id_family AND
				table3.id_family_member=table1.id_family_member AND
				table3.id_event='$id_event' 

				");

			$sth->execute();

			$qry_registrations = null;
				} 
				catch (PDOException $e) {
				print "Error!  Please email steve@cenational.org";
				die();
			}

			/* Fetch all of the remaining rows in the result set */

			$array_registrations = $sth->fetchAll(PDO::FETCH_ASSOC);
?>
<form action="test_code.php" method="post" enctype="application/x-www-form-urlencoded" id="form1">
    <table border="1" align="center">
        <tr>
            <td colspan="3" align="center"><h2>&nbsp;</h2></td>
        </tr>
        <tr>
            <td>ID Family Member</td>
            <td>Record Commitment</td>
        </tr>
        
    <?php
    	$x=1;
         foreach ($array_registrations as $sub_registrations) {
			 $id_family_member_button=$sub_registrations['id_family_member'];
			 ?>
            <tr>
                <td><?php echo $sub_registrations['id_family_member'];?></td>
                <td align="center">

                        <input type="text" name="id_event" id="id_event" value="<?php echo $id_event;?>" />
                        <input type="text" name="id_family_member" id="id_family_member" value="<?php echo $id_family_member_button;?>" />
                        <input type="submit" name="button" id="button" value="Submit" />
                </td>
                        
            </tr>
        <?php } ?>

</table>
</form>

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Receiving page code

echo "<pre>";
var_export($_POST);
echo "</pre>";

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