Anyone knows how to put a date of birth in this

Hi all,

How do I add Date of birth to this form

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<form id="join_form" name="join_form" method="post" action="member.php" class="form_advanced">
<table>
<tr>
<td><label>User Name:</label></td>
<td><input type="text" name="ID" class="clsLoginTextbox required" minlength="2" onblur="Checkuser(this.value)" /></td>
</tr>

<tr>
<td><label>First Name:</label></td>
<td><input type="text" class="clsLoginTextbox required" name="FirstName" minlength="2"/></td>
</tr>

<tr>
<td><label>Last Name:</label></td>
<td><input type="text" class="clsLoginTextbox required" name="LastName" minlength="2"/></td>
</tr>
<tr>
<td><label>Password:</label></td>
<td><input type="password" name="Password" class="clsLoginTextbox required" id="password" minlength="5"/></td>
</tr>
<tr>
<td><label>Retype Password:</label></td>
<td><input class="clsLoginTextbox required" equalTo="#password" type="password" name="Password_conform" /></td>
</tr>
<tr>
<td><label>Email:</label></td>
<td><input class="clsLoginTextbox required email" type="text" name="Email" minlength="6"/></td>
</tr>
<tr>
<td><label>I am:</label></td>
<td><select class="required" name="gender" id="gender">
<option value="male">Male</option>
<option value="female">Female</option>
</select>
</td>

</tr>
<tr>
<td>&nbsp;</td>
<td><input class="clsLoginbut" type="submit" name="submit" value="Join" /></td>
</tr>
</table>
</form>
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Any help would be appreciated.