[akz645]

These were my settings:
http://i.imgur.com/jI48mDH.png
I tried on vBulletin 4.2.3 and it almost worked- the gender options doesn't show when users are editing their profile.
Like me, if you put: No, but display at registration in the User Profile Field, then you'll need to do what I write below:

So in order to fix that:
AdminCP -> Styles & Templates -> Search Templates -> tb_homepage [Pick your style too] -> modifyprofile (edit)
Find:

PHP Code:

                    <input type="hidden" name="coppauser" value="1" />
                    <p class="description">
                        {vb:rawphrase if_under_13_provide_parent}
                    </p>
                </div> 


Originally Posted by imported_df+++++

ADD BELOW:

<div class="blockrow">
				<ul class="group">
					<li>
<label for="gender">{vb:rawphrase gender}:</label>
<select class="primary" name="userfield[fieldXX]" id="cfield_XX" tabindex="1">
<option value="0" selected="selected"></option>
<option value="1">Male</option>
<option value="2">Female</option> 
</select>
<input type="hidden" name="userfield[fieldXX_set]" value="1" />
					</li>
				</ul>
			</div>

change XX for whatever your profile field for gender is.

That seems to do the trick.
If you have problems with it appearing on the registration, then do what the guy above me said to do in the registration template.

It will be located here:
http://i.imgur.com/7RpGMzK.png

The blank option is useful, so users can hide gender from appearing in the postbit altogether.

Edit:
I'd suggest ignoring this post. Do what I did in the post below (much better/easier).