Labels, checkboxes and radio buttons - checkbox

Question

My web application uses forms laid out as in the example below...
First Name [____________]
Last Name [____________]
Gender () Male () Female
The markup I use is something like...
<label for="firstName">First Name</label><input type="text" id="firstName" />
<label for="lastName">Last Name</label><input type="text" id="lastName" />
<label>Gender</label>
<fieldset>
<legend>Gender</legend>
<input type="radio" name="sex" id="sex-m" value="m">
<label for="sex-m">Male</label>
<input type="radio" name="sex" id="sex-f" value="f">
<label for="sex-f">Female</label>
</fieldset>
I have the following issues that I don't know how to solve...
I want to have the WHOLE GROUP of radio buttons labelled like any other field (as in the diagram above), but there is nothing to link the label to (i.e. nothing for its "for" attribute, since each radio in the group has its own label just for the value of the individual radio button) A label without a "for" attribute will not pass accessibility compliance.
The <legend> element of the fieldset seems to duplicate the function of the label. Is this really necessary?
I had thought about styling the <legend> tag to appear as though it's a label, and dispense with the label altogether for the radio button group, but that seems a bit hacky to me, and will also introduce complexities elsewhere in my code (which relies on <label> elements to do some nifty validation message markup and various other things)
Thanks in advance.

Answer 1

The first part of Ssollinger's answer is correct:
The code should be:
<label for="firstName">First Name</label><input type="text" id="firstName" />
<label for="lastName">Last Name</label><input type="text" id="lastName" />
<fieldset>
<legend>Gender</legend>
<input type="radio" name="sex" id="sex-m" value="m">
<label for="sex-m">Male</label>
<input type="radio" name="sex" id="sex-f" value="f">
<label for="sex-f">Female</label>
</fieldset>
When assistive technology hits the male radio button, most will read as: "Gender: male radio button 1 of 2 not selected."
Then you could use CSS on the fieldset, legend, the labels and inputs. If memory serves correctly fieldsets can be a bear to style, so i might end up adding a <div> to it:
<label for="firstName">First Name</label><input type="text" id="firstName" />
<label for="lastName">Last Name</label><input type="text" id="lastName" />
<fieldset>
<legend>Gender</legend>
<div>
<input type="radio" name="sex" id="sex-m" value="m">
<label for="sex-m">Male</label>
<input type="radio" name="sex" id="sex-f" value="f">
<label for="sex-f">Female</label>
</div>
</fieldset>
Adding this <div> has no accessibility implications.
Like in the comment in ssollinger's answer, you could dump the fieldset and legend approach, but you would need to build everything to make it accessible, an example of a build out

Answer 2

I had thought about styling the <legend> tag to appear as though it's a label, and dispense with the label altogether for the radio button group, …
This is the correct way to do it. "Gender" is not a label for anything, the labels for the radio boxes are "male" and "female". "Gender" is the legend of the fieldset which groups the radio buttons together. The correct way to implement this form is to remove the "Gender" label and just leave the fieldset with legend "Gender".
Technically, you could probably add a <div> around the radio buttons and point the for= of the "Gender" label to that, but I'm quite sure that this will cause accessibility problems (haven't tried it with a screen reader though) so I would strongly recommend to get rid of the label for "Gender".